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n2n/src/edge_utils.c
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fengdaolong 92dfa67e22 Added DHCP function embedded in sn. 
1. Automatically assign IP addresses to the edge through the DHCP function that comes with sn, the default IP address pool is 172.17.12.0/24.
2. The -d parameter is added to sn, and the IP address pool of the embedded DHCP can be customized.
3. Now edge does not need to add -a and -s parameters to automatically obtain the IP address.
4. The IP automatically obtained by the cross-community edge can be the same, because the communities are isolated from each other and do not interfere with each other.
5. On the management side of sn (127.0.0.1:5645), you can now view the IP address of the tutap adapter of each edge.
6. Fix many bugs that have a certain chance of causing memory leaks.
7. Note: This version is not fully compatible with the previous version.
2020-08-08 22:40:45 +08:00

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/**
* (C) 2007-20 - ntop.org and contributors
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not see see <http://www.gnu.org/licenses/>
*
*/
#include "n2n.h"
#include "edge_utils_win32.h"
/* heap allocation for compression as per lzo example doc */
#define HEAP_ALLOC(var,size) lzo_align_t __LZO_MMODEL var [ ((size) + (sizeof(lzo_align_t) - 1)) / sizeof(lzo_align_t) ]
static HEAP_ALLOC(wrkmem, LZO1X_1_MEM_COMPRESS);
/* ************************************** */
static const char * supernode_ip(const n2n_edge_t * eee);
static void send_register(n2n_edge_t *eee, const n2n_sock_t *remote_peer, const n2n_mac_t peer_mac);
static void check_peer_registration_needed(n2n_edge_t * eee,
uint8_t from_supernode,
const n2n_mac_t mac,
const n2n_sock_t * peer);
static int edge_init_sockets(n2n_edge_t *eee, int udp_local_port, int mgmt_port, uint8_t tos);
static int edge_init_routes(n2n_edge_t *eee, n2n_route_t *routes, uint16_t num_routes);
static void edge_cleanup_routes(n2n_edge_t *eee);
static int supernode2addr(n2n_sock_t * sn, const n2n_sn_name_t addrIn);
static void check_known_peer_sock_change(n2n_edge_t * eee,
uint8_t from_supernode,
const n2n_mac_t mac,
const n2n_sock_t * peer,
time_t when);
/* ************************************** */
int edge_verify_conf(const n2n_edge_conf_t *conf) {
if(conf->community_name[0] == 0)
return(-1);
if(conf->sn_num == 0)
return(-2);
if(conf->register_interval < 1)
return(-3);
if(((conf->encrypt_key == NULL) && (conf->transop_id != N2N_TRANSFORM_ID_NULL)) ||
((conf->encrypt_key != NULL) && (conf->transop_id == N2N_TRANSFORM_ID_NULL)))
return(-4);
return(0);
}
/* ************************************** */
void edge_set_callbacks(n2n_edge_t *eee, const n2n_edge_callbacks_t *callbacks) {
memcpy(&eee->cb, callbacks, sizeof(n2n_edge_callbacks_t));
}
/* ************************************** */
void edge_set_userdata(n2n_edge_t *eee, void *user_data) {
eee->user_data = user_data;
}
/* ************************************** */
void* edge_get_userdata(n2n_edge_t *eee) {
return(eee->user_data);
}
/* ************************************** */
int edge_get_n2n_socket(n2n_edge_t *eee) {
return(eee->udp_sock);
}
/* ************************************** */
int edge_get_management_socket(n2n_edge_t *eee) {
return(eee->udp_mgmt_sock);
}
/* ************************************** */
const char* transop_str(enum n2n_transform tr) {
switch(tr) {
case N2N_TRANSFORM_ID_NULL: return("null");
case N2N_TRANSFORM_ID_TWOFISH: return("twofish");
case N2N_TRANSFORM_ID_AESCBC: return("AES-CBC");
case N2N_TRANSFORM_ID_CHACHA20:return("ChaCha20");
case N2N_TRANSFORM_ID_SPECK :return("Speck");
default: return("invalid");
};
}
/* ************************************** */
const char* compression_str(uint8_t cmpr) {
switch(cmpr) {
case N2N_COMPRESSION_ID_NONE: return("none");
case N2N_COMPRESSION_ID_LZO: return("lzo1x");
#ifdef HAVE_LIBZSTD
case N2N_COMPRESSION_ID_ZSTD: return("zstd");
#endif
default: return("invalid");
};
}
/* ************************************** */
/** Destination 01:00:5E:00:00:00 - 01:00:5E:7F:FF:FF is multicast ethernet.
*/
static int is_ethMulticast(const void * buf, size_t bufsize) {
int retval = 0;
/* Match 01:00:5E:00:00:00 - 01:00:5E:7F:FF:FF */
if(bufsize >= sizeof(ether_hdr_t)) {
/* copy to aligned memory */
ether_hdr_t eh;
memcpy(&eh, buf, sizeof(ether_hdr_t));
if((0x01 == eh.dhost[0]) &&
(0x00 == eh.dhost[1]) &&
(0x5E == eh.dhost[2]) &&
(0 == (0x80 & eh.dhost[3])))
retval = 1; /* This is an ethernet multicast packet [RFC1112]. */
}
return retval;
}
/* ************************************** */
/** Destination MAC 33:33:0:00:00:00 - 33:33:FF:FF:FF:FF is reserved for IPv6
* neighbour discovery.
*/
static int is_ip6_discovery(const void * buf, size_t bufsize) {
int retval = 0;
if(bufsize >= sizeof(ether_hdr_t)) {
/* copy to aligned memory */
ether_hdr_t eh;
memcpy(&eh, buf, sizeof(ether_hdr_t));
if((0x33 == eh.dhost[0]) && (0x33 == eh.dhost[1]))
retval = 1; /* This is an IPv6 multicast packet [RFC2464]. */
}
return retval;
}
/* ************************************** */
/** Initialise an edge to defaults.
*
* This also initialises the NULL transform operation opstruct.
*/
n2n_edge_t* edge_init(const n2n_edge_conf_t *conf, int *rv) {
n2n_transform_t transop_id = conf->transop_id;
n2n_edge_t *eee = calloc(1, sizeof(n2n_edge_t));
int rc = -1, i;
if((rc = edge_verify_conf(conf)) != 0) {
traceEvent(TRACE_ERROR, "Invalid configuration");
goto edge_init_error;
}
if(!eee) {
traceEvent(TRACE_ERROR, "Cannot allocate memory");
goto edge_init_error;
}
#ifdef WIN32
initWin32();
#endif
memcpy(&eee->conf, conf, sizeof(*conf));
eee->start_time = time(NULL);
eee->known_peers = NULL;
eee->pending_peers = NULL;
eee->sup_attempts = N2N_EDGE_SUP_ATTEMPTS;
eee->sn_last_valid_time_stamp = initial_time_stamp ();
pearson_hash_init();
if(eee->conf.compression == N2N_COMPRESSION_ID_LZO)
if(lzo_init() != LZO_E_OK) {
traceEvent(TRACE_ERROR, "LZO compression error");
goto edge_init_error;
}
#ifdef N2N_HAVE_ZSTD
// zstd does not require initialization. if it were required, this would be a good place
#endif
for(i=0; i<eee->conf.sn_num; ++i)
traceEvent(TRACE_NORMAL, "supernode %u => %s\n", i, (eee->conf.sn_ip_array[i]));
/* Set the active supernode */
supernode2addr(&(eee->supernode), eee->conf.sn_ip_array[eee->sn_idx]);
/* Set active transop */
switch(transop_id) {
case N2N_TRANSFORM_ID_TWOFISH:
rc = n2n_transop_twofish_init(&eee->conf, &eee->transop);
break;
#ifdef N2N_HAVE_AES
case N2N_TRANSFORM_ID_AESCBC:
rc = n2n_transop_aes_cbc_init(&eee->conf, &eee->transop);
break;
#endif
#ifdef HAVE_OPENSSL_1_1
case N2N_TRANSFORM_ID_CHACHA20:
rc = n2n_transop_cc20_init(&eee->conf, &eee->transop);
break;
#endif
case N2N_TRANSFORM_ID_SPECK:
rc = n2n_transop_speck_init(&eee->conf, &eee->transop);
break;
default:
rc = n2n_transop_null_init(&eee->conf, &eee->transop);
}
if((rc < 0) || (eee->transop.fwd == NULL) || (eee->transop.transform_id != transop_id)) {
traceEvent(TRACE_ERROR, "Transop init failed");
goto edge_init_error;
}
/* Set the key schedule (context) for header encryption if enabled */
if(conf->header_encryption == HEADER_ENCRYPTION_ENABLED) {
traceEvent(TRACE_NORMAL, "Header encryption is enabled.");
packet_header_setup_key ((char *)(eee->conf.community_name), &(eee->conf.header_encryption_ctx),&(eee->conf.header_iv_ctx));
}
if(eee->transop.no_encryption)
traceEvent(TRACE_WARNING, "Encryption is disabled in edge");
if(edge_init_sockets(eee, eee->conf.local_port, eee->conf.mgmt_port, eee->conf.tos) < 0) {
traceEvent(TRACE_ERROR, "socket setup failed");
goto edge_init_error;
}
if(edge_init_routes(eee, eee->conf.routes, eee->conf.num_routes) < 0) {
traceEvent(TRACE_ERROR, "routes setup failed");
goto edge_init_error;
}
//edge_init_success:
*rv = 0;
return(eee);
edge_init_error:
if(eee)
free(eee);
*rv = rc;
return(NULL);
}
/* ************************************** */
static int find_and_remove_peer(struct peer_info **head, const n2n_mac_t mac) {
struct peer_info *peer;
HASH_FIND_PEER(*head, mac, peer);
if(peer) {
HASH_DEL(*head, peer);
free(peer);
return(1);
}
return(0);
}
/* ************************************** */
static uint32_t localhost_v4 = 0x7f000001;
static uint8_t localhost_v6[IPV6_SIZE] = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1};
/* Exclude localhost as it may be received when an edge node runs
* in the same supernode host.
*/
static int is_valid_peer_sock(const n2n_sock_t *sock) {
switch(sock->family) {
case AF_INET:
{
uint32_t *a = (uint32_t*)sock->addr.v4;
if(*a != htonl(localhost_v4))
return(1);
}
break;
case AF_INET6:
if(memcmp(sock->addr.v6, localhost_v6, IPV6_SIZE))
return(1);
break;
}
return(0);
}
/* ***************************************************** */
/** Resolve the supernode IP address.
*
* REVISIT: This is a really bad idea. The edge will block completely while the
* hostname resolution is performed. This could take 15 seconds.
*/
static int supernode2addr(n2n_sock_t * sn, const n2n_sn_name_t addrIn) {
n2n_sn_name_t addr;
const char *supernode_host;
int rv = 0;
memcpy(addr, addrIn, N2N_EDGE_SN_HOST_SIZE);
supernode_host = strtok(addr, ":");
if(supernode_host) {
in_addr_t sn_addr;
char *supernode_port = strtok(NULL, ":");
const struct addrinfo aihints = {0, PF_INET, 0, 0, 0, NULL, NULL, NULL};
struct addrinfo * ainfo = NULL;
int nameerr;
if(supernode_port)
sn->port = atoi(supernode_port);
else
traceEvent(TRACE_WARNING, "Bad supernode parameter (-l <host:port>) %s %s:%s",
addr, supernode_host, supernode_port);
nameerr = getaddrinfo(supernode_host, NULL, &aihints, &ainfo);
if(0 == nameerr)
{
struct sockaddr_in * saddr;
/* ainfo s the head of a linked list if non-NULL. */
if(ainfo && (PF_INET == ainfo->ai_family))
{
/* It is definitely and IPv4 address -> sockaddr_in */
saddr = (struct sockaddr_in *)ainfo->ai_addr;
memcpy(sn->addr.v4, &(saddr->sin_addr.s_addr), IPV4_SIZE);
sn->family=AF_INET;
}
else
{
/* Should only return IPv4 addresses due to aihints. */
traceEvent(TRACE_WARNING, "Failed to resolve supernode IPv4 address for %s", supernode_host);
rv = -1;
}
freeaddrinfo(ainfo); /* free everything allocated by getaddrinfo(). */
ainfo = NULL;
} else {
traceEvent(TRACE_WARNING, "Failed to resolve supernode host %s", supernode_host);
rv = -2;
}
} else {
traceEvent(TRACE_WARNING, "Wrong supernode parameter (-l <host:port>)");
rv = -3;
}
return(rv);
}
/* ************************************** */
static const int definitely_from_supernode = 1;
/***
*
* For a given packet, find the apporopriate internal last valid time stamp for lookup
* and verify it (and also update, if applicable).
*/
static int find_peer_time_stamp_and_verify (n2n_edge_t * eee,
int from_supernode, const n2n_mac_t mac,
uint64_t stamp) {
uint64_t * previous_stamp = NULL;
if(from_supernode) {
// from supernode
previous_stamp = &(eee->sn_last_valid_time_stamp);
} else {
// from (peer) edge
struct peer_info *peer;
HASH_FIND_PEER(eee->pending_peers, mac, peer);
if(!peer) {
HASH_FIND_PEER(eee->known_peers, mac, peer);
}
if(peer) {
// time_stamp_verify_and_update allows the pointer a previous stamp to be NULL
// if it is a (so far) unknown peer
previous_stamp = &(peer->last_valid_time_stamp);
}
}
// failure --> 0; success --> 1
return ( time_stamp_verify_and_update (stamp, previous_stamp) );
}
/* ************************************** */
/***
*
* Register over multicast in case there is a peer on the same network listening
*/
static void register_with_local_peers(n2n_edge_t * eee) {
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
if(eee->multicast_joined && eee->conf.allow_p2p) {
/* send registration to the local multicast group */
traceEvent(TRACE_DEBUG, "Registering with multicast group %s:%u",
N2N_MULTICAST_GROUP, N2N_MULTICAST_PORT);
send_register(eee, &(eee->multicast_peer), NULL);
}
#else
traceEvent(TRACE_DEBUG, "Multicast peers discovery is disabled, skipping");
#endif
}
/* ************************************** */
/** Start the registration process.
*
* If the peer is already in pending_peers, ignore the request.
* If not in pending_peers, add it and send a REGISTER.
*
* If hdr is for a direct peer-to-peer packet, try to register back to sender
* even if the MAC is in pending_peers. This is because an incident direct
* packet indicates that peer-to-peer exchange should work so more aggressive
* registration can be permitted (once per incoming packet) as this should only
* last for a small number of packets..
*
* Called from the main loop when Rx a packet for our device mac.
*/
static void register_with_new_peer(n2n_edge_t * eee,
uint8_t from_supernode,
const n2n_mac_t mac,
const n2n_sock_t * peer) {
/* REVISIT: purge of pending_peers not yet done. */
struct peer_info * scan;
macstr_t mac_buf;
n2n_sock_str_t sockbuf;
HASH_FIND_PEER(eee->pending_peers, mac, scan);
/* NOTE: pending_peers are purged periodically with purge_expired_registrations */
if(scan == NULL) {
scan = calloc(1, sizeof(struct peer_info));
memcpy(scan->mac_addr, mac, N2N_MAC_SIZE);
scan->sock = *peer;
scan->timeout = REGISTER_SUPER_INTERVAL_DFL; /* TODO: should correspond to the peer supernode registration timeout */
scan->last_seen = time(NULL); /* Don't change this it marks the pending peer for removal. */
scan->last_valid_time_stamp = initial_time_stamp ();
HASH_ADD_PEER(eee->pending_peers, scan);
traceEvent(TRACE_DEBUG, "=== new pending %s -> %s",
macaddr_str(mac_buf, scan->mac_addr),
sock_to_cstr(sockbuf, &(scan->sock)));
traceEvent(TRACE_DEBUG, "Pending peers list size=%u",
HASH_COUNT(eee->pending_peers));
/* trace Sending REGISTER */
if(from_supernode) {
/* UDP NAT hole punching through supernode. Send to peer first(punch local UDP hole)
* and then ask supernode to forward. Supernode then ask peer to ack. Some nat device
* drop and block ports with incoming UDP packet if out-come traffic does not exist.
* So we can alternatively set TTL so that the packet sent to peer never really reaches
* The register_ttl is basically nat level + 1. Set it to 1 means host like DMZ.
*/
if(eee->conf.register_ttl == 1) {
/* We are DMZ host or port is directly accessible. Just let peer to send back the ack */
#ifndef WIN32
} else if(eee->conf.register_ttl > 1) {
/* Setting register_ttl usually implies that the edge knows the internal net topology
* clearly, we can apply aggressive port prediction to support incoming Symmetric NAT
*/
int curTTL = 0;
socklen_t lenTTL = sizeof(int);
n2n_sock_t sock = scan->sock;
int alter = 16; /* TODO: set by command line or more reliable prediction method */
getsockopt(eee->udp_sock, IPPROTO_IP, IP_TTL, (void *)(char *)&curTTL, &lenTTL);
setsockopt(eee->udp_sock, IPPROTO_IP, IP_TTL,
(void *)(char *)&eee->conf.register_ttl,
sizeof(eee->conf.register_ttl));
for (; alter > 0; alter--, sock.port++)
{
send_register(eee, &sock, mac);
}
setsockopt(eee->udp_sock, IPPROTO_IP, IP_TTL, (void *)(char *)&curTTL, sizeof(curTTL));
#endif
} else { /* eee->conf.register_ttl <= 0 */
/* Normal STUN */
send_register(eee, &(scan->sock), mac);
}
send_register(eee, &(eee->supernode), mac);
} else {
/* P2P register, send directly */
send_register(eee, &(scan->sock), mac);
}
register_with_local_peers(eee);
} else
scan->sock = *peer;
}
/* ************************************** */
/** Update the last_seen time for this peer, or get registered. */
static void check_peer_registration_needed(n2n_edge_t * eee,
uint8_t from_supernode,
const n2n_mac_t mac,
const n2n_sock_t * peer) {
struct peer_info *scan;
HASH_FIND_PEER(eee->known_peers, mac, scan);
if(scan == NULL) {
/* Not in known_peers - start the REGISTER process. */
register_with_new_peer(eee, from_supernode, mac, peer);
} else {
/* Already in known_peers. */
time_t now = time(NULL);
if(!from_supernode)
scan->last_p2p = now;
if((now - scan->last_seen) > 0 /* >= 1 sec */) {
/* Don't register too often */
check_known_peer_sock_change(eee, from_supernode, mac, peer, now);
}
}
}
/* ************************************** */
/* Confirm that a pending peer is reachable directly via P2P.
*
* peer must be a pointer to an element of the pending_peers list.
*/
static void peer_set_p2p_confirmed(n2n_edge_t * eee,
const n2n_mac_t mac,
const n2n_sock_t * peer,
time_t now) {
struct peer_info *scan;
macstr_t mac_buf;
n2n_sock_str_t sockbuf;
HASH_FIND_PEER(eee->pending_peers, mac, scan);
if(scan) {
HASH_DEL(eee->pending_peers, scan);
/* Add scan to known_peers. */
HASH_ADD_PEER(eee->known_peers, scan);
scan->sock = *peer;
scan->last_p2p = now;
traceEvent(TRACE_DEBUG, "P2P connection established: %s [%s]",
macaddr_str(mac_buf, mac),
sock_to_cstr(sockbuf, peer));
traceEvent(TRACE_DEBUG, "=== new peer %s -> %s",
macaddr_str(mac_buf, scan->mac_addr),
sock_to_cstr(sockbuf, &(scan->sock)));
traceEvent(TRACE_DEBUG, "Pending peers list size=%u",
HASH_COUNT(eee->pending_peers));
traceEvent(TRACE_DEBUG, "Known peers list size=%u",
HASH_COUNT(eee->known_peers));
scan->last_seen = now;
} else
traceEvent(TRACE_DEBUG, "Failed to find sender in pending_peers.");
}
/* ************************************** */
int is_empty_ip_address(const n2n_sock_t * sock) {
const uint8_t * ptr=NULL;
size_t len=0;
size_t i;
if(AF_INET6 == sock->family)
{
ptr = sock->addr.v6;
len = 16;
}
else
{
ptr = sock->addr.v4;
len = 4;
}
for (i=0; i<len; ++i)
{
if(0 != ptr[i])
{
/* found a non-zero byte in address */
return 0;
}
}
return 1;
}
/* ************************************** */
static const n2n_mac_t broadcast_mac = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
static const n2n_mac_t null_mac = {0, 0, 0, 0, 0, 0};
/** Check if a known peer socket has changed and possibly register again.
*/
static void check_known_peer_sock_change(n2n_edge_t * eee,
uint8_t from_supernode,
const n2n_mac_t mac,
const n2n_sock_t * peer,
time_t when) {
struct peer_info *scan;
n2n_sock_str_t sockbuf1;
n2n_sock_str_t sockbuf2; /* don't clobber sockbuf1 if writing two addresses to trace */
macstr_t mac_buf;
if(is_empty_ip_address(peer))
return;
if(!memcmp(mac, broadcast_mac, N2N_MAC_SIZE))
return;
/* Search the peer in known_peers */
HASH_FIND_PEER(eee->known_peers, mac, scan);
if(!scan)
/* Not in known_peers */
return;
if(!sock_equal(&(scan->sock), peer)) {
if(!from_supernode) {
/* This is a P2P packet */
traceEvent(TRACE_NORMAL, "Peer changed %s: %s -> %s",
macaddr_str(mac_buf, scan->mac_addr),
sock_to_cstr(sockbuf1, &(scan->sock)),
sock_to_cstr(sockbuf2, peer));
/* The peer has changed public socket. It can no longer be assumed to be reachable. */
HASH_DEL(eee->known_peers, scan);
free(scan);
register_with_new_peer(eee, from_supernode, mac, peer);
} else {
/* Don't worry about what the supernode reports, it could be seeing a different socket. */
}
} else
scan->last_seen = when;
}
/* ************************************** */
/** Send a datagram to a socket defined by a n2n_sock_t */
static ssize_t sendto_sock(int fd, const void * buf,
size_t len, const n2n_sock_t * dest) {
struct sockaddr_in peer_addr;
ssize_t sent;
if(!dest->family)
// Invalid socket
return 0;
fill_sockaddr((struct sockaddr *) &peer_addr,
sizeof(peer_addr),
dest);
sent = sendto(fd, buf, len, 0/*flags*/,
(struct sockaddr *)&peer_addr, sizeof(struct sockaddr_in));
if(sent < 0)
{
char * c = strerror(errno);
traceEvent(TRACE_ERROR, "sendto failed (%d) %s", errno, c);
}
else
{
traceEvent(TRACE_DEBUG, "sendto sent=%d to ", (signed int)sent);
}
return sent;
}
/* ************************************** */
/* Bind eee->udp_multicast_sock to multicast group */
static void check_join_multicast_group(n2n_edge_t *eee) {
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
if(!eee->multicast_joined) {
struct ip_mreq mreq;
mreq.imr_multiaddr.s_addr = inet_addr(N2N_MULTICAST_GROUP);
mreq.imr_interface.s_addr = htonl(INADDR_ANY);
if(setsockopt(eee->udp_multicast_sock, IPPROTO_IP, IP_ADD_MEMBERSHIP, (char *)&mreq, sizeof(mreq)) < 0) {
traceEvent(TRACE_WARNING, "Failed to bind to local multicast group %s:%u [errno %u]",
N2N_MULTICAST_GROUP, N2N_MULTICAST_PORT, errno);
#ifdef WIN32
traceEvent(TRACE_ERROR, "WSAGetLastError(): %u", WSAGetLastError());
#endif
} else {
traceEvent(TRACE_NORMAL, "Successfully joined multicast group %s:%u",
N2N_MULTICAST_GROUP, N2N_MULTICAST_PORT);
eee->multicast_joined = 1;
}
}
#endif
}
/* ************************************** */
/** Send a REGISTER_SUPER packet to the current supernode. */
static void send_register_super(n2n_edge_t *eee, const n2n_sock_t *supernode, int sn_idx) {
uint8_t pktbuf[N2N_PKT_BUF_SIZE] = {0};
size_t idx;
/* ssize_t sent; */
n2n_common_t cmn;
n2n_REGISTER_SUPER_t reg;
n2n_sock_str_t sockbuf;
memset(&cmn, 0, sizeof(cmn));
memset(&reg, 0, sizeof(reg));
cmn.ttl = N2N_DEFAULT_TTL;
cmn.pc = n2n_register_super;
cmn.flags = 0;
memcpy(cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE);
for (idx = 0; (sn_idx==0) && (idx < N2N_COOKIE_SIZE); ++idx)
eee->last_cookie[idx] = n2n_rand() % 0xff;
memcpy(reg.cookie, eee->last_cookie, N2N_COOKIE_SIZE);
reg.dev_addr.net_addr = ntohl(eee->device.ip_addr);
reg.dev_addr.net_bitlen = mask2bitlen(ntohl(eee->device.device_mask));
reg.auth.scheme = 0; /* No auth yet */
idx = 0;
encode_mac(reg.edgeMac, &idx, eee->device.mac_addr);
idx = 0;
encode_REGISTER_SUPER(pktbuf, &idx, &cmn, &reg);
traceEvent(TRACE_DEBUG, "send REGISTER_SUPER to %s",
sock_to_cstr(sockbuf, supernode));
if (eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED)
packet_header_encrypt(pktbuf, idx, eee->conf.header_encryption_ctx,
eee->conf.header_iv_ctx,
time_stamp(), pearson_hash_16(pktbuf, idx));
/* sent = */ sendto_sock(eee->udp_sock, pktbuf, idx, supernode);
}
/* ************************************** */
/** Send a QUERY_PEER packet to the current supernode. */
static void send_query_peer( n2n_edge_t * eee,
const n2n_mac_t dstMac) {
uint8_t pktbuf[N2N_PKT_BUF_SIZE];
size_t idx;
n2n_common_t cmn = {0};
n2n_QUERY_PEER_t query = {{0}};
cmn.ttl=N2N_DEFAULT_TTL;
cmn.pc = n2n_query_peer;
cmn.flags = 0;
memcpy( cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE );
idx=0;
encode_mac( query.srcMac, &idx, eee->device.mac_addr );
idx=0;
encode_mac( query.targetMac, &idx, dstMac );
idx=0;
encode_QUERY_PEER( pktbuf, &idx, &cmn, &query );
traceEvent( TRACE_DEBUG, "send QUERY_PEER to supernode" );
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED){
packet_header_encrypt (pktbuf, idx, eee->conf.header_encryption_ctx,
eee->conf.header_iv_ctx,
time_stamp (), pearson_hash_16 (pktbuf, idx));
}
sendto_sock( eee->udp_sock, pktbuf, idx, &(eee->supernode) );
}
/** Send a REGISTER packet to another edge. */
static void send_register(n2n_edge_t * eee,
const n2n_sock_t * remote_peer,
const n2n_mac_t peer_mac) {
uint8_t pktbuf[N2N_PKT_BUF_SIZE];
size_t idx;
/* ssize_t sent; */
n2n_common_t cmn;
n2n_REGISTER_t reg;
n2n_sock_str_t sockbuf;
if(!eee->conf.allow_p2p) {
traceEvent(TRACE_DEBUG, "Skipping register as P2P is disabled");
return;
}
memset(&cmn, 0, sizeof(cmn));
memset(&reg, 0, sizeof(reg));
cmn.ttl=N2N_DEFAULT_TTL;
cmn.pc = n2n_register;
cmn.flags = 0;
memcpy(cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE);
idx=0;
encode_uint32(reg.cookie, &idx, 123456789);
idx=0;
encode_mac(reg.srcMac, &idx, eee->device.mac_addr);
if(peer_mac) {
/* Can be NULL for multicast registrations */
idx=0;
encode_mac(reg.dstMac, &idx, peer_mac);
}
idx=0;
encode_REGISTER(pktbuf, &idx, &cmn, &reg);
traceEvent(TRACE_INFO, "Send REGISTER to %s",
sock_to_cstr(sockbuf, remote_peer));
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED)
packet_header_encrypt (pktbuf, idx, eee->conf.header_encryption_ctx,
eee->conf.header_iv_ctx,
time_stamp (), pearson_hash_16 (pktbuf, idx));
/* sent = */ sendto_sock(eee->udp_sock, pktbuf, idx, remote_peer);
}
/* ************************************** */
/** Send a REGISTER_ACK packet to a peer edge. */
static void send_register_ack(n2n_edge_t * eee,
const n2n_sock_t * remote_peer,
const n2n_REGISTER_t * reg) {
uint8_t pktbuf[N2N_PKT_BUF_SIZE];
size_t idx;
/* ssize_t sent; */
n2n_common_t cmn;
n2n_REGISTER_ACK_t ack;
n2n_sock_str_t sockbuf;
if(!eee->conf.allow_p2p) {
traceEvent(TRACE_DEBUG, "Skipping register ACK as P2P is disabled");
return;
}
memset(&cmn, 0, sizeof(cmn));
memset(&ack, 0, sizeof(reg));
cmn.ttl=N2N_DEFAULT_TTL;
cmn.pc = n2n_register_ack;
cmn.flags = 0;
memcpy(cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE);
memset(&ack, 0, sizeof(ack));
memcpy(ack.cookie, reg->cookie, N2N_COOKIE_SIZE);
memcpy(ack.srcMac, eee->device.mac_addr, N2N_MAC_SIZE);
memcpy(ack.dstMac, reg->srcMac, N2N_MAC_SIZE);
idx=0;
encode_REGISTER_ACK(pktbuf, &idx, &cmn, &ack);
traceEvent(TRACE_INFO, "send REGISTER_ACK %s",
sock_to_cstr(sockbuf, remote_peer));
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED)
packet_header_encrypt (pktbuf, idx, eee->conf.header_encryption_ctx,
eee->conf.header_iv_ctx,
time_stamp (), pearson_hash_16 (pktbuf, idx));
/* sent = */ sendto_sock(eee->udp_sock, pktbuf, idx, remote_peer);
}
/* ************************************** */
/** @brief Check to see if we should re-register with the supernode.
*
* This is frequently called by the main loop.
*/
void update_supernode_reg(n2n_edge_t * eee, time_t nowTime) {
u_int sn_idx;
if(eee->sn_wait && (nowTime > (eee->last_register_req + (eee->conf.register_interval/10)))) {
/* fall through */
traceEvent(TRACE_DEBUG, "update_supernode_reg: doing fast retry.");
} else if(nowTime < (eee->last_register_req + eee->conf.register_interval))
return; /* Too early */
check_join_multicast_group(eee);
if(0 == eee->sup_attempts) {
/* Give up on that supernode and try the next one. */
++(eee->sn_idx);
if(eee->sn_idx >= eee->conf.sn_num) {
/* Got to end of list, go back to the start. Also works for list of one entry. */
eee->sn_idx=0;
}
traceEvent(TRACE_WARNING, "Supernode not responding, now trying %s", supernode_ip(eee));
eee->sup_attempts = N2N_EDGE_SUP_ATTEMPTS;
}
else
--(eee->sup_attempts);
for(sn_idx=0; sn_idx<eee->conf.sn_num; sn_idx++) {
if(supernode2addr(&(eee->supernode), eee->conf.sn_ip_array[sn_idx]) == 0) {
traceEvent(TRACE_INFO, "Registering with supernode [id: %u/%u][%s][attempts left %u]",
sn_idx+1, eee->conf.sn_num,
supernode_ip(eee), (unsigned int)eee->sup_attempts);
send_register_super(eee, &(eee->supernode), sn_idx);
}
}
register_with_local_peers(eee);
eee->sn_wait=1;
/* REVISIT: turn-on gratuitous ARP with config option. */
/* send_grat_arps(sock_fd, is_udp_sock); */
eee->last_register_req = nowTime;
}
/* ************************************** */
/** NOT IMPLEMENTED
*
* This would send a DEREGISTER packet to a peer edge or supernode to indicate
* the edge is going away.
*/
static void send_deregister(n2n_edge_t * eee,
n2n_sock_t * remote_peer) {
/* Marshall and send message */
}
/* ************************************** */
/** Return the IP address of the current supernode in the ring. */
static const char * supernode_ip(const n2n_edge_t * eee) {
return (eee->conf.sn_ip_array)[eee->sn_idx];
}
/* ************************************** */
/** A PACKET has arrived containing an encapsulated ethernet datagram - usually
* encrypted. */
static int handle_PACKET(n2n_edge_t * eee,
const n2n_common_t * cmn,
const n2n_PACKET_t * pkt,
const n2n_sock_t * orig_sender,
uint8_t * payload,
size_t psize) {
ssize_t data_sent_len;
uint8_t from_supernode;
uint8_t * eth_payload=NULL;
int retval = -1;
time_t now;
ether_hdr_t * eh;
ipstr_t ip_buf;
now = time(NULL);
traceEvent(TRACE_DEBUG, "handle_PACKET size %u transform %u",
(unsigned int)psize, (unsigned int)pkt->transform);
/* hexdump(payload, psize); */
from_supernode= cmn->flags & N2N_FLAGS_FROM_SUPERNODE;
if(from_supernode)
{
if(!memcmp(pkt->dstMac, broadcast_mac, N2N_MAC_SIZE))
++(eee->stats.rx_sup_broadcast);
++(eee->stats.rx_sup);
eee->last_sup=now;
}
else
{
++(eee->stats.rx_p2p);
eee->last_p2p=now;
}
/* Update the sender in peer table entry */
check_peer_registration_needed(eee, from_supernode, pkt->srcMac, orig_sender);
/* Handle transform. */
{
uint8_t decodebuf[N2N_PKT_BUF_SIZE];
size_t eth_size;
n2n_transform_t rx_transop_id;
rx_transop_id = (n2n_transform_t)pkt->transform;
/* optional compression is encoded in uppermost bit of transform field.
* this is an intermediate solution to maintain compatibility until some
* upcoming major release (3.0?) brings up changes in packet structure anyway
* in the course of which a dedicated compression field could be spent.
* REVISIT then. */
uint16_t rx_compression_id;
rx_compression_id = (uint16_t)rx_transop_id >> (8*sizeof((uint16_t)rx_transop_id)-N2N_COMPRESSION_ID_BITLEN);
rx_transop_id &= (1 << (8*sizeof((uint16_t)rx_transop_id)-N2N_COMPRESSION_ID_BITLEN)) -1;
if(rx_transop_id == eee->conf.transop_id) {
uint8_t is_multicast;
eth_payload = decodebuf;
eh = (ether_hdr_t*)eth_payload;
eth_size = eee->transop.rev(&eee->transop,
eth_payload, N2N_PKT_BUF_SIZE,
payload, psize, pkt->srcMac);
++(eee->transop.rx_cnt); /* stats */
/* decompress if necessary */
uint8_t * deflation_buffer = 0;
int32_t deflated_len;
switch (rx_compression_id) {
case N2N_COMPRESSION_ID_NONE:
break; // continue afterwards
case N2N_COMPRESSION_ID_LZO:
deflation_buffer = malloc (N2N_PKT_BUF_SIZE);
lzo1x_decompress (eth_payload, eth_size, deflation_buffer, (lzo_uint*)&deflated_len, NULL);
break;
#ifdef N2N_HAVE_ZSTD
case N2N_COMPRESSION_ID_ZSTD:
deflated_len = N2N_PKT_BUF_SIZE;
deflation_buffer = malloc (deflated_len);
deflated_len = (int32_t)ZSTD_decompress (deflation_buffer, deflated_len, eth_payload, eth_size);
if(ZSTD_isError(deflated_len)) {
traceEvent (TRACE_ERROR, "payload decompression failed with zstd error '%s'.",
ZSTD_getErrorName(deflated_len));
free (deflation_buffer);
return (-1); // cannot help it
}
break;
#endif
default:
traceEvent (TRACE_ERROR, "payload decompression failed: received packet indicating unsupported %s compression.",
compression_str(rx_compression_id));
return (-1); // cannot handle it
}
if(rx_compression_id) {
traceEvent (TRACE_DEBUG, "payload decompression [%s]: deflated %u bytes to %u bytes",
compression_str(rx_compression_id), eth_size, (int)deflated_len);
memcpy(eth_payload ,deflation_buffer, deflated_len );
eth_size = deflated_len;
free (deflation_buffer);
}
is_multicast = (is_ip6_discovery(eth_payload, eth_size) || is_ethMulticast(eth_payload, eth_size));
if(eee->conf.drop_multicast && is_multicast) {
traceEvent(TRACE_INFO, "Dropping RX multicast");
return(-1);
} else if((!eee->conf.allow_routing) && (!is_multicast)) {
/* Check if it is a routed packet */
if((ntohs(eh->type) == 0x0800) && (eth_size >= ETH_FRAMESIZE + IP4_MIN_SIZE)) {
uint32_t *dst = (uint32_t*)&eth_payload[ETH_FRAMESIZE + IP4_DSTOFFSET];
uint8_t *dst_mac = (uint8_t*)eth_payload;
/* Note: all elements of the_ip are in network order */
if(!memcmp(dst_mac, broadcast_mac, N2N_MAC_SIZE))
traceEvent(TRACE_DEBUG, "Broadcast packet [%s]",
intoa(ntohl(*dst), ip_buf, sizeof(ip_buf)));
else if((*dst != eee->device.ip_addr)) {
/* This is a packet that needs to be routed */
traceEvent(TRACE_INFO, "Discarding routed packet [%s]",
intoa(ntohl(*dst), ip_buf, sizeof(ip_buf)));
return(-1);
} else {
/* This packet is directed to us */
/* traceEvent(TRACE_INFO, "Sending non-routed packet"); */
}
}
}
if(eee->cb.packet_from_peer) {
uint16_t tmp_eth_size = eth_size;
if(eee->cb.packet_from_peer(eee, orig_sender, eth_payload, &tmp_eth_size) == N2N_DROP) {
traceEvent(TRACE_DEBUG, "DROP packet %u", (unsigned int)eth_size);
return(0);
}
eth_size = tmp_eth_size;
}
/* Write ethernet packet to tap device. */
traceEvent(TRACE_DEBUG, "sending to TAP %u", (unsigned int)eth_size);
data_sent_len = tuntap_write(&(eee->device), eth_payload, eth_size);
if(data_sent_len == eth_size)
{
retval = 0;
}
}
else
{
traceEvent(TRACE_ERROR, "invalid transop ID: expected %s(%u), got %s(%u)",
transop_str(eee->conf.transop_id), eee->conf.transop_id,
transop_str(rx_transop_id), rx_transop_id);
}
}
return retval;
}
/* ************************************** */
/** Read a datagram from the management UDP socket and take appropriate
* action. */
static void readFromMgmtSocket(n2n_edge_t * eee, int * keep_running) {
uint8_t udp_buf[N2N_PKT_BUF_SIZE]; /* Compete UDP packet */
ssize_t recvlen;
/* ssize_t sendlen; */
struct sockaddr_in sender_sock;
socklen_t i;
size_t msg_len;
time_t now;
now = time(NULL);
i = sizeof(sender_sock);
recvlen = recvfrom(eee->udp_mgmt_sock, udp_buf, N2N_PKT_BUF_SIZE, 0/*flags*/,
(struct sockaddr *)&sender_sock, (socklen_t*)&i);
if(recvlen < 0)
{
traceEvent(TRACE_ERROR, "mgmt recvfrom failed with %s", strerror(errno));
return; /* failed to receive data from UDP */
}
if(recvlen >= 4)
{
if(0 == memcmp(udp_buf, "stop", 4))
{
traceEvent(TRACE_ERROR, "stop command received.");
*keep_running = 0;
return;
}
if(0 == memcmp(udp_buf, "help", 4))
{
msg_len=0;
setTraceLevel(getTraceLevel()+1);
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"Help for edge management console:\n"
" stop Gracefully exit edge\n"
" help This help message\n"
" +verb Increase verbosity of logging\n"
" -verb Decrease verbosity of logging\n"
" <enter> Display statistics\n\n");
sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
(struct sockaddr *)&sender_sock, sizeof(struct sockaddr_in));
return;
}
}
if(recvlen >= 5)
{
if(0 == memcmp(udp_buf, "+verb", 5))
{
msg_len=0;
setTraceLevel(getTraceLevel()+1);
traceEvent(TRACE_ERROR, "+verb traceLevel=%u", (unsigned int)getTraceLevel());
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"> +OK traceLevel=%u\n", (unsigned int)getTraceLevel());
sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
(struct sockaddr *)&sender_sock, sizeof(struct sockaddr_in));
return;
}
if(0 == memcmp(udp_buf, "-verb", 5))
{
msg_len=0;
if(getTraceLevel() > 0)
{
setTraceLevel(getTraceLevel()-1);
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"> -OK traceLevel=%u\n", getTraceLevel());
}
else
{
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"> -NOK traceLevel=%u\n", getTraceLevel());
}
traceEvent(TRACE_ERROR, "-verb traceLevel=%u", (unsigned int)getTraceLevel());
sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
(struct sockaddr *)&sender_sock, sizeof(struct sockaddr_in));
return;
}
}
traceEvent(TRACE_DEBUG, "mgmt status rq");
msg_len=0;
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"Statistics for edge\n");
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"uptime %lu\n",
time(NULL) - eee->start_time);
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"paths super:%u,%u p2p:%u,%u\n",
(unsigned int)eee->stats.tx_sup,
(unsigned int)eee->stats.rx_sup,
(unsigned int)eee->stats.tx_p2p,
(unsigned int)eee->stats.rx_p2p);
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"transop |%6u|%6u|\n",
(unsigned int)eee->transop.tx_cnt,
(unsigned int)eee->transop.rx_cnt);
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"peers pend:%u full:%u\n",
HASH_COUNT(eee->pending_peers),
HASH_COUNT(eee->known_peers));
msg_len += snprintf((char *)(udp_buf+msg_len), (N2N_PKT_BUF_SIZE-msg_len),
"last super:%lu(%ld sec ago) p2p:%lu(%ld sec ago)\n",
eee->last_sup, (now-eee->last_sup), eee->last_p2p,
(now-eee->last_p2p));
traceEvent(TRACE_DEBUG, "mgmt status sending: %s", udp_buf);
/* sendlen = */ sendto(eee->udp_mgmt_sock, udp_buf, msg_len, 0/*flags*/,
(struct sockaddr *)&sender_sock, sizeof(struct sockaddr_in));
}
/* ************************************** */
static int check_query_peer_info(n2n_edge_t *eee, time_t now, n2n_mac_t mac) {
struct peer_info *scan;
HASH_FIND_PEER(eee->pending_peers, mac, scan);
if(!scan) {
scan = calloc(1, sizeof(struct peer_info));
memcpy(scan->mac_addr, mac, N2N_MAC_SIZE);
scan->timeout = REGISTER_SUPER_INTERVAL_DFL; /* TODO: should correspond to the peer supernode registration timeout */
scan->last_seen = now; /* Don't change this it marks the pending peer for removal. */
scan->last_valid_time_stamp = initial_time_stamp ();
HASH_ADD_PEER(eee->pending_peers, scan);
}
if(now - scan->last_sent_query > REGISTER_SUPER_INTERVAL_DFL) {
send_query_peer(eee, scan->mac_addr);
scan->last_sent_query = now;
return(0);
}
return(1);
}
/* ************************************** */
/* @return 1 if destination is a peer, 0 if destination is supernode */
static int find_peer_destination(n2n_edge_t * eee,
n2n_mac_t mac_address,
n2n_sock_t * destination) {
struct peer_info *scan;
macstr_t mac_buf;
n2n_sock_str_t sockbuf;
int retval=0;
time_t now = time(NULL);
if(!memcmp(mac_address, broadcast_mac, N2N_MAC_SIZE)) {
traceEvent(TRACE_DEBUG, "Broadcast destination peer, using supernode");
memcpy(destination, &(eee->supernode), sizeof(struct sockaddr_in));
return(0);
}
traceEvent(TRACE_DEBUG, "Searching destination peer for MAC %02X:%02X:%02X:%02X:%02X:%02X",
mac_address[0] & 0xFF, mac_address[1] & 0xFF, mac_address[2] & 0xFF,
mac_address[3] & 0xFF, mac_address[4] & 0xFF, mac_address[5] & 0xFF);
HASH_FIND_PEER(eee->known_peers, mac_address, scan);
if(scan && (scan->last_seen > 0)) {
if((now - scan->last_p2p) >= (scan->timeout / 2)) {
/* Too much time passed since we saw the peer, need to register again
* since the peer address may have changed. */
traceEvent(TRACE_DEBUG, "Refreshing idle known peer");
HASH_DEL(eee->known_peers, scan);
free(scan);
/* NOTE: registration will be performed upon the receival of the next response packet */
} else {
/* Valid known peer found */
memcpy(destination, &scan->sock, sizeof(n2n_sock_t));
retval=1;
}
}
if(retval == 0) {
memcpy(destination, &(eee->supernode), sizeof(struct sockaddr_in));
traceEvent(TRACE_DEBUG, "P2P Peer [MAC=%02X:%02X:%02X:%02X:%02X:%02X] not found, using supernode",
mac_address[0] & 0xFF, mac_address[1] & 0xFF, mac_address[2] & 0xFF,
mac_address[3] & 0xFF, mac_address[4] & 0xFF, mac_address[5] & 0xFF);
check_query_peer_info(eee, now, mac_address);
}
traceEvent(TRACE_DEBUG, "find_peer_address (%s) -> [%s]",
macaddr_str(mac_buf, mac_address),
sock_to_cstr(sockbuf, destination));
return retval;
}
/* ***************************************************** */
/** Send an ecapsulated ethernet PACKET to a destination edge or broadcast MAC
* address. */
static int send_packet(n2n_edge_t * eee,
n2n_mac_t dstMac,
const uint8_t * pktbuf,
size_t pktlen) {
int is_p2p;
/*ssize_t s; */
n2n_sock_str_t sockbuf;
n2n_sock_t destination;
macstr_t mac_buf;
/* hexdump(pktbuf, pktlen); */
is_p2p = find_peer_destination(eee, dstMac, &destination);
if(is_p2p)
++(eee->stats.tx_p2p);
else {
++(eee->stats.tx_sup);
if(!memcmp(dstMac, broadcast_mac, N2N_MAC_SIZE))
++(eee->stats.tx_sup_broadcast);
}
traceEvent(TRACE_INFO, "Tx PACKET to %s (dest=%s) [%u B]",
sock_to_cstr(sockbuf, &destination),
macaddr_str(mac_buf, dstMac), pktlen);
/* s = */ sendto_sock(eee->udp_sock, pktbuf, pktlen, &destination);
return 0;
}
/* ************************************** */
/** A layer-2 packet was received at the tunnel and needs to be sent via UDP. */
void edge_send_packet2net(n2n_edge_t * eee,
uint8_t *tap_pkt, size_t len) {
ipstr_t ip_buf;
n2n_mac_t destMac;
n2n_common_t cmn;
n2n_PACKET_t pkt;
uint8_t pktbuf[N2N_PKT_BUF_SIZE];
size_t idx=0;
n2n_transform_t tx_transop_idx = eee->transop.transform_id;
ether_hdr_t eh;
/* tap_pkt is not aligned so we have to copy to aligned memory */
memcpy(&eh, tap_pkt, sizeof(ether_hdr_t));
/* Discard IP packets that are not originated by this hosts */
if(!(eee->conf.allow_routing)) {
if(ntohs(eh.type) == 0x0800) {
/* This is an IP packet from the local source address - not forwarded. */
uint32_t *src = (uint32_t*)&tap_pkt[ETH_FRAMESIZE + IP4_SRCOFFSET];
/* Note: all elements of the_ip are in network order */
if(*src != eee->device.ip_addr) {
/* This is a packet that needs to be routed */
traceEvent(TRACE_INFO, "Discarding routed packet [%s]",
intoa(ntohl(*src), ip_buf, sizeof(ip_buf)));
return;
} else {
/* This packet is originated by us */
/* traceEvent(TRACE_INFO, "Sending non-routed packet"); */
}
}
}
/* Optionally compress then apply transforms, eg encryption. */
/* Once processed, send to destination in PACKET */
memcpy(destMac, tap_pkt, N2N_MAC_SIZE); /* dest MAC is first in ethernet header */
memset(&cmn, 0, sizeof(cmn));
cmn.ttl = N2N_DEFAULT_TTL;
cmn.pc = n2n_packet;
cmn.flags=0; /* no options, not from supernode, no socket */
memcpy(cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE);
memset(&pkt, 0, sizeof(pkt));
memcpy(pkt.srcMac, eee->device.mac_addr, N2N_MAC_SIZE);
memcpy(pkt.dstMac, destMac, N2N_MAC_SIZE);
pkt.sock.family=0; /* do not encode sock */
pkt.transform = tx_transop_idx;
// compression needs to be tried before encode_PACKET is called for compression indication gets encoded there
pkt.compression = N2N_COMPRESSION_ID_NONE;
if(eee->conf.compression) {
uint8_t * compression_buffer = NULL;
int32_t compression_len;
switch (eee->conf.compression) {
case N2N_COMPRESSION_ID_LZO:
compression_buffer = malloc (len + len / 16 + 64 + 3);
if(lzo1x_1_compress(tap_pkt, len, compression_buffer, (lzo_uint*)&compression_len, wrkmem) == LZO_E_OK) {
if(compression_len < len) {
pkt.compression = N2N_COMPRESSION_ID_LZO;
}
}
break;
#ifdef N2N_HAVE_ZSTD
case N2N_COMPRESSION_ID_ZSTD:
compression_len = N2N_PKT_BUF_SIZE + 128;
compression_buffer = malloc (compression_len); // leaves enough room, for exact size call compression_len = ZSTD_compressBound (len); (slower)
compression_len = (int32_t)ZSTD_compress(compression_buffer, compression_len, tap_pkt, len, ZSTD_COMPRESSION_LEVEL) ;
if(!ZSTD_isError(compression_len)) {
if(compression_len < len) {
pkt.compression = N2N_COMPRESSION_ID_ZSTD;
}
} else {
traceEvent (TRACE_ERROR, "payload compression failed with zstd error '%s'.",
ZSTD_getErrorName(compression_len));
free (compression_buffer);
// continue with unset without pkt.compression --> will send uncompressed
}
break;
#endif
default:
break;
}
if(pkt.compression) {
traceEvent (TRACE_DEBUG, "payload compression [%s]: compressed %u bytes to %u bytes\n",
compression_str(pkt.compression), len, compression_len);
memcpy (tap_pkt, compression_buffer, compression_len);
len = compression_len;
free (compression_buffer);
}
}
/* optional compression is encoded in uppermost bits of transform field.
* this is an intermediate solution to maintain compatibility until some
* upcoming major release (3.0?) brings up changes in packet structure anyway
* in the course of which a dedicated compression field could be spent.
* REVISIT then. */
pkt.transform = pkt.transform | (pkt.compression << (8*sizeof(pkt.transform)-N2N_COMPRESSION_ID_BITLEN));
idx=0;
encode_PACKET(pktbuf, &idx, &cmn, &pkt);
uint16_t headerIdx = idx;
idx += eee->transop.fwd(&eee->transop,
pktbuf+idx, N2N_PKT_BUF_SIZE-idx,
tap_pkt, len, pkt.dstMac);
traceEvent(TRACE_DEBUG, "Encode %u B PACKET [%u B data, %u B overhead] transform %u",
(u_int)idx, (u_int)len, (u_int)(idx-len), tx_transop_idx);
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED)
packet_header_encrypt (pktbuf, headerIdx, eee->conf.header_encryption_ctx,
eee->conf.header_iv_ctx,
time_stamp (), pearson_hash_16 (pktbuf, idx));
#ifdef MTU_ASSERT_VALUE
{
const u_int eth_udp_overhead = ETH_FRAMESIZE + IP4_MIN_SIZE + UDP_SIZE;
// MTU assertion which avoids fragmentation by N2N
assert(idx + eth_udp_overhead <= MTU_ASSERT_VALUE);
}
#endif
eee->transop.tx_cnt++; /* stats */
send_packet(eee, destMac, pktbuf, idx); /* to peer or supernode */
}
/* ************************************** */
/** Read a single packet from the TAP interface, process it and write out the
* corresponding packet to the cooked socket.
*/
void edge_read_from_tap(n2n_edge_t * eee) {
/* tun -> remote */
uint8_t eth_pkt[N2N_PKT_BUF_SIZE];
macstr_t mac_buf;
ssize_t len;
len = tuntap_read( &(eee->device), eth_pkt, N2N_PKT_BUF_SIZE );
if((len <= 0) || (len > N2N_PKT_BUF_SIZE))
{
traceEvent(TRACE_WARNING, "read()=%d [%d/%s]",
(signed int)len, errno, strerror(errno));
traceEvent(TRACE_WARNING, "TAP I/O operation aborted, restart later.");
sleep(3);
tuntap_close(&(eee->device));
tuntap_open(&(eee->device), eee->tuntap_priv_conf.tuntap_dev_name, eee->tuntap_priv_conf.ip_mode, eee->tuntap_priv_conf.ip_addr,
eee->tuntap_priv_conf.netmask, eee->tuntap_priv_conf.device_mac, eee->tuntap_priv_conf.mtu);
}
else
{
const uint8_t * mac = eth_pkt;
traceEvent(TRACE_DEBUG, "### Rx TAP packet (%4d) for %s",
(signed int)len, macaddr_str(mac_buf, mac));
if(eee->conf.drop_multicast &&
(is_ip6_discovery(eth_pkt, len) ||
is_ethMulticast(eth_pkt, len)
)
)
{
traceEvent(TRACE_INFO, "Dropping TX multicast");
}
else
{
if(eee->cb.packet_from_tap) {
uint16_t tmp_len = len;
if(eee->cb.packet_from_tap(eee, eth_pkt, &tmp_len) == N2N_DROP) {
traceEvent(TRACE_DEBUG, "DROP packet %u", (unsigned int)len);
return;
}
len = tmp_len;
}
edge_send_packet2net(eee, eth_pkt, len);
}
}
}
/* ************************************** */
/* ************************************** */
/** Read a datagram from the main UDP socket to the internet. */
void readFromIPSocket(n2n_edge_t * eee, int in_sock) {
n2n_common_t cmn; /* common fields in the packet header */
n2n_sock_str_t sockbuf1;
n2n_sock_str_t sockbuf2; /* don't clobber sockbuf1 if writing two addresses to trace */
macstr_t mac_buf1;
macstr_t mac_buf2;
uint8_t udp_buf[N2N_PKT_BUF_SIZE]; /* Compete UDP packet */
ssize_t recvlen;
size_t rem;
size_t idx;
size_t msg_type;
uint8_t from_supernode;
struct sockaddr_in sender_sock;
n2n_sock_t sender;
n2n_sock_t * orig_sender=NULL;
time_t now=0;
uint64_t stamp = 0;
size_t i;
i = sizeof(sender_sock);
recvlen = recvfrom(in_sock, udp_buf, N2N_PKT_BUF_SIZE, 0/*flags*/,
(struct sockaddr *)&sender_sock, (socklen_t*)&i);
if(recvlen < 0) {
#ifdef WIN32
if(WSAGetLastError() != WSAECONNRESET)
#endif
{
traceEvent(TRACE_ERROR, "recvfrom() failed %d errno %d (%s)", recvlen, errno, strerror(errno));
#ifdef WIN32
traceEvent(TRACE_ERROR, "WSAGetLastError(): %u", WSAGetLastError());
#endif
}
return; /* failed to receive data from UDP */
}
/* REVISIT: when UDP/IPv6 is supported we will need a flag to indicate which
* IP transport version the packet arrived on. May need to UDP sockets. */
sender.family = AF_INET; /* UDP socket was opened PF_INET v4 */
sender.port = ntohs(sender_sock.sin_port);
memcpy(&(sender.addr.v4), &(sender_sock.sin_addr.s_addr), IPV4_SIZE);
/* The packet may not have an orig_sender socket spec. So default to last
* hop as sender. */
orig_sender=&sender;
traceEvent(TRACE_DEBUG, "### Rx N2N UDP (%d) from %s",
(signed int)recvlen, sock_to_cstr(sockbuf1, &sender));
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED) {
uint16_t checksum = 0;
if( packet_header_decrypt (udp_buf, recvlen, (char *)eee->conf.community_name, eee->conf.header_encryption_ctx,
eee->conf.header_iv_ctx,
&stamp, &checksum) == 0) {
traceEvent(TRACE_DEBUG, "readFromIPSocket failed to decrypt header.");
return;
}
// time stamp verification follows in the packet specific section as it requires to determine the
// sender from the hash list by its MAC, or the packet might be from the supernode, this all depends
// on packet type, path taken (via supernode) and packet structure (MAC is not always in the same place)
if (checksum != pearson_hash_16 (udp_buf, recvlen)) {
traceEvent(TRACE_DEBUG, "readFromIPSocket dropped packet due to checksum error.");
return;
}
}
/* hexdump(udp_buf, recvlen); */
rem = recvlen; /* Counts down bytes of packet to protect against buffer overruns. */
idx = 0; /* marches through packet header as parts are decoded. */
if(decode_common(&cmn, udp_buf, &rem, &idx) < 0)
{
traceEvent(TRACE_ERROR, "Failed to decode common section in N2N_UDP");
return; /* failed to decode packet */
}
now = time(NULL);
msg_type = cmn.pc; /* packet code */
from_supernode= cmn.flags & N2N_FLAGS_FROM_SUPERNODE;
if(0 == memcmp(cmn.community, eee->conf.community_name, N2N_COMMUNITY_SIZE)) {
switch(msg_type) {
case MSG_TYPE_PACKET:
{
/* process PACKET - most frequent so first in list. */
n2n_PACKET_t pkt;
decode_PACKET(&pkt, &cmn, udp_buf, &rem, &idx);
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED) {
if(!find_peer_time_stamp_and_verify (eee, from_supernode, pkt.srcMac, stamp)) {
traceEvent(TRACE_DEBUG, "readFromIPSocket dropped PACKET due to time stamp error.");
return;
}
}
if(is_valid_peer_sock(&pkt.sock))
orig_sender = &(pkt.sock);
if(!from_supernode) {
/* This is a P2P packet from the peer. We purge a pending
* registration towards the possibly nat-ted peer address as we now have
* a valid channel. We still use check_peer_registration_needed in
* handle_PACKET to double check this.
*/
traceEvent(TRACE_DEBUG, "Got P2P packet");
traceEvent(TRACE_DEBUG, "[P2P] Rx data from %s [%u B]", sock_to_cstr(sockbuf1, &sender), recvlen);
find_and_remove_peer(&eee->pending_peers, pkt.srcMac);
}
else {
/* [PsP] : edge Peer->Supernode->edge Peer */
traceEvent(TRACE_DEBUG, "[PsP] Rx data from %s (Via=%s) [%u B]",
sock_to_cstr(sockbuf2, orig_sender), sock_to_cstr(sockbuf1, &sender), recvlen);
}
handle_PACKET(eee, &cmn, &pkt, orig_sender, udp_buf+idx, recvlen-idx);
break;
}
case MSG_TYPE_REGISTER:
{
/* Another edge is registering with us */
n2n_REGISTER_t reg;
int via_multicast;
decode_REGISTER(&reg, &cmn, udp_buf, &rem, &idx);
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED) {
if(!find_peer_time_stamp_and_verify (eee, from_supernode, reg.srcMac, stamp)) {
traceEvent(TRACE_DEBUG, "readFromIPSocket dropped REGISTER due to time stamp error.");
return;
}
}
if(is_valid_peer_sock(&reg.sock))
orig_sender = &(reg.sock);
via_multicast = !memcmp(reg.dstMac, null_mac, N2N_MAC_SIZE);
if(via_multicast && !memcmp(reg.srcMac, eee->device.mac_addr, N2N_MAC_SIZE)) {
traceEvent(TRACE_DEBUG, "Skipping REGISTER from self");
break;
}
if(!via_multicast && memcmp(reg.dstMac, eee->device.mac_addr, N2N_MAC_SIZE)) {
traceEvent(TRACE_DEBUG, "Skipping REGISTER for other peer");
break;
}
if(!from_supernode) {
/* This is a P2P registration from the peer. We purge a pending
* registration towards the possibly nat-ted peer address as we now have
* a valid channel. We still use check_peer_registration_needed below
* to double check this.
*/
traceEvent(TRACE_DEBUG, "Got P2P register");
traceEvent(TRACE_INFO, "[P2P] Rx REGISTER from %s", sock_to_cstr(sockbuf1, &sender));
find_and_remove_peer(&eee->pending_peers, reg.srcMac);
/* NOTE: only ACK to peers */
send_register_ack(eee, orig_sender, &reg);
}
else {
traceEvent(TRACE_INFO, "[PsP] Rx REGISTER src=%s dst=%s from sn=%s (edge:%s)",
macaddr_str(mac_buf1, reg.srcMac), macaddr_str(mac_buf2, reg.dstMac),
sock_to_cstr(sockbuf1, &sender), sock_to_cstr(sockbuf2, orig_sender));
}
check_peer_registration_needed(eee, from_supernode, reg.srcMac, orig_sender);
break;
}
case MSG_TYPE_REGISTER_ACK:
{
/* Peer edge is acknowledging our register request */
n2n_REGISTER_ACK_t ra;
decode_REGISTER_ACK(&ra, &cmn, udp_buf, &rem, &idx);
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED) {
if(!find_peer_time_stamp_and_verify (eee, !definitely_from_supernode, ra.srcMac, stamp)) {
traceEvent(TRACE_DEBUG, "readFromIPSocket dropped REGISTER_ACK due to time stamp error.");
return;
}
}
if(is_valid_peer_sock(&ra.sock))
orig_sender = &(ra.sock);
traceEvent(TRACE_INFO, "Rx REGISTER_ACK src=%s dst=%s from peer %s (%s)",
macaddr_str(mac_buf1, ra.srcMac),
macaddr_str(mac_buf2, ra.dstMac),
sock_to_cstr(sockbuf1, &sender),
sock_to_cstr(sockbuf2, orig_sender));
peer_set_p2p_confirmed(eee, ra.srcMac, &sender, now);
break;
}
case MSG_TYPE_REGISTER_SUPER_ACK:
{
in_addr_t net;
char * ip_str = NULL;
n2n_REGISTER_SUPER_ACK_t ra;
memset(&ra, 0, sizeof(n2n_REGISTER_SUPER_ACK_t));
// Indicates successful connection between the edge and SN nodes
static int bTrace = 1;
if (bTrace)
{
traceEvent(TRACE_NORMAL, "[OK] Edge Peer <<< ================ >>> Super Node");
bTrace = 0;
}
if(eee->sn_wait)
{
decode_REGISTER_SUPER_ACK(&ra, &cmn, udp_buf, &rem, &idx);
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED) {
if(!find_peer_time_stamp_and_verify (eee, definitely_from_supernode, null_mac, stamp)) {
traceEvent(TRACE_DEBUG, "readFromIPSocket dropped REGISTER_SUPER_ACK due to time stamp error.");
return;
}
}
if(is_valid_peer_sock(&ra.sock))
orig_sender = &(ra.sock);
traceEvent(TRACE_INFO, "Rx REGISTER_SUPER_ACK myMAC=%s [%s] (external %s). Attempts %u",
macaddr_str(mac_buf1, ra.edgeMac),
sock_to_cstr(sockbuf1, &sender),
sock_to_cstr(sockbuf2, orig_sender),
(unsigned int)eee->sup_attempts);
if(memcmp(ra.edgeMac, eee->device.mac_addr, N2N_MAC_SIZE)) {
traceEvent(TRACE_INFO, "readFromIPSocket dropped REGISTER_SUPER_ACK due to wrong addressing.");
return;
}
if(0 == memcmp(ra.cookie, eee->last_cookie, N2N_COOKIE_SIZE))
{
if(ra.num_sn > 0)
{
traceEvent(TRACE_NORMAL, "Rx REGISTER_SUPER_ACK backup supernode at %s",
sock_to_cstr(sockbuf1, &(ra.sn_bak)));
}
eee->last_sup = now;
eee->sn_wait=0;
eee->sup_attempts = N2N_EDGE_SUP_ATTEMPTS; /* refresh because we got a response */
if (eee->conf.tuntap_ip_mode == TUNTAP_IP_MODE_SN_ASSIGN) {
if ((ra.dev_addr.net_addr != 0) && (ra.dev_addr.net_bitlen != 0)) {
net = htonl(ra.dev_addr.net_addr);
if ((ip_str = inet_ntoa(*(struct in_addr *) &net)) != NULL) {
strncpy(eee->tuntap_priv_conf.ip_addr, ip_str,
N2N_NETMASK_STR_SIZE);
}
net = htonl(bitlen2mask(ra.dev_addr.net_bitlen));
if ((ip_str = inet_ntoa(*(struct in_addr *) &net)) != NULL) {
strncpy(eee->tuntap_priv_conf.netmask, ip_str,
N2N_NETMASK_STR_SIZE);
}
}
}
if(eee->cb.sn_registration_updated)
eee->cb.sn_registration_updated(eee, now, &sender);
/* NOTE: the register_interval should be chosen by the edge node
* based on its NAT configuration. */
//eee->conf.register_interval = ra.lifetime;
}
else
{
traceEvent(TRACE_INFO, "Rx REGISTER_SUPER_ACK with wrong or old cookie.");
}
}
else
{
traceEvent(TRACE_INFO, "Rx REGISTER_SUPER_ACK with no outstanding REGISTER_SUPER.");
}
break;
}
case MSG_TYPE_PEER_INFO: {
n2n_PEER_INFO_t pi;
struct peer_info * scan;
decode_PEER_INFO( &pi, &cmn, udp_buf, &rem, &idx );
if(eee->conf.header_encryption == HEADER_ENCRYPTION_ENABLED) {
if(!find_peer_time_stamp_and_verify (eee, definitely_from_supernode, null_mac, stamp)) {
traceEvent(TRACE_DEBUG, "readFromIPSocket dropped PEER_INFO due to time stamp error.");
return;
}
}
if(!is_valid_peer_sock(&pi.sock)) {
traceEvent(TRACE_DEBUG, "Skip invalid PEER_INFO %s [%s]",
sock_to_cstr(sockbuf1, &pi.sock),
macaddr_str(mac_buf1, pi.mac) );
break;
}
HASH_FIND_PEER(eee->pending_peers, pi.mac, scan);
if(scan) {
scan->sock = pi.sock;
traceEvent(TRACE_INFO, "Rx PEER_INFO for %s: is at %s",
macaddr_str(mac_buf1, pi.mac),
sock_to_cstr(sockbuf1, &pi.sock));
send_register(eee, &scan->sock, scan->mac_addr);
} else {
traceEvent(TRACE_INFO, "Rx PEER_INFO unknown peer %s",
macaddr_str(mac_buf1, pi.mac) );
}
break;
}
default:
/* Not a known message type */
traceEvent(TRACE_WARNING, "Unable to handle packet type %d: ignored", (signed int)msg_type);
return;
} /* switch(msg_type) */
} else if(from_supernode) /* if(community match) */
traceEvent(TRACE_WARNING, "Received packet with unknown community");
else
traceEvent(TRACE_INFO, "Ignoring packet with unknown community");
}
/* ************************************** */
void print_edge_stats(const n2n_edge_t *eee) {
const struct n2n_edge_stats *s = &eee->stats;
traceEvent(TRACE_NORMAL, "**********************************");
traceEvent(TRACE_NORMAL, "Packet stats:");
traceEvent(TRACE_NORMAL, " TX P2P: %u pkts", s->tx_p2p);
traceEvent(TRACE_NORMAL, " RX P2P: %u pkts", s->rx_p2p);
traceEvent(TRACE_NORMAL, " TX Supernode: %u pkts (%u broadcast)", s->tx_sup, s->tx_sup_broadcast);
traceEvent(TRACE_NORMAL, " RX Supernode: %u pkts (%u broadcast)", s->rx_sup, s->rx_sup_broadcast);
traceEvent(TRACE_NORMAL, "**********************************");
}
/* ************************************** */
int run_edge_loop(n2n_edge_t * eee, int *keep_running) {
size_t numPurged;
time_t lastIfaceCheck=0;
time_t lastTransop=0;
time_t last_purge_known = 0;
time_t last_purge_pending = 0;
#ifdef WIN32
struct tunread_arg arg;
arg.eee = eee;
arg.keep_running = keep_running;
HANDLE tun_read_thread = startTunReadThread(&arg);
#endif
*keep_running = 1;
update_supernode_reg(eee, time(NULL));
/* Main loop
*
* select() is used to wait for input on either the TAP fd or the UDP/TCP
* socket. When input is present the data is read and processed by either
* readFromIPSocket() or edge_read_from_tap()
*/
while(*keep_running) {
int rc, max_sock = 0;
fd_set socket_mask;
struct timeval wait_time;
time_t nowTime;
FD_ZERO(&socket_mask);
FD_SET(eee->udp_sock, &socket_mask);
FD_SET(eee->udp_mgmt_sock, &socket_mask);
max_sock = max(eee->udp_sock, eee->udp_mgmt_sock);
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
FD_SET(eee->udp_multicast_sock, &socket_mask);
max_sock = max(eee->udp_sock, eee->udp_multicast_sock);
#endif
#ifndef WIN32
FD_SET(eee->device.fd, &socket_mask);
max_sock = max(max_sock, eee->device.fd);
#endif
wait_time.tv_sec = SOCKET_TIMEOUT_INTERVAL_SECS; wait_time.tv_usec = 0;
rc = select(max_sock+1, &socket_mask, NULL, NULL, &wait_time);
nowTime=time(NULL);
/* Make sure ciphers are updated before the packet is treated. */
if((nowTime - lastTransop) > TRANSOP_TICK_INTERVAL) {
lastTransop = nowTime;
eee->transop.tick(&eee->transop, nowTime);
}
if(rc > 0) {
/* Any or all of the FDs could have input; check them all. */
if(FD_ISSET(eee->udp_sock, &socket_mask)) {
/* Read a cooked socket from the internet socket (unicast). Writes on the TAP
* socket. */
readFromIPSocket(eee, eee->udp_sock);
}
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
if(FD_ISSET(eee->udp_multicast_sock, &socket_mask)) {
/* Read a cooked socket from the internet socket (multicast). Writes on the TAP
* socket. */
traceEvent(TRACE_DEBUG, "Received packet from multicast socket");
readFromIPSocket(eee, eee->udp_multicast_sock);
}
#endif
if(FD_ISSET(eee->udp_mgmt_sock, &socket_mask)) {
/* Read a cooked socket from the internet socket. Writes on the TAP
* socket. */
readFromMgmtSocket(eee, keep_running);
if(!(*keep_running))
break;
}
#ifndef WIN32
if(FD_ISSET(eee->device.fd, &socket_mask)) {
/* Read an ethernet frame from the TAP socket. Write on the IP
* socket. */
edge_read_from_tap(eee);
}
#endif
}
/* Finished processing select data. */
update_supernode_reg(eee, nowTime);
numPurged = purge_expired_registrations(&eee->known_peers, &last_purge_known);
numPurged += purge_expired_registrations(&eee->pending_peers, &last_purge_pending);
if(numPurged > 0) {
traceEvent(TRACE_INFO, "%u peers removed. now: pending=%u, operational=%u",
numPurged,
HASH_COUNT(eee->pending_peers),
HASH_COUNT(eee->known_peers));
}
if((eee->conf.tuntap_ip_mode == TUNTAP_IP_MODE_DHCP) &&
((nowTime - lastIfaceCheck) > IFACE_UPDATE_INTERVAL)) {
uint32_t old_ip = eee->device.ip_addr;
traceEvent(TRACE_NORMAL, "Re-checking dynamic IP address.");
tuntap_get_address(&(eee->device));
lastIfaceCheck = nowTime;
if((old_ip != eee->device.ip_addr) && eee->cb.ip_address_changed)
eee->cb.ip_address_changed(eee, old_ip, eee->device.ip_addr);
}
if (eee->cb.main_loop_period)
eee->cb.main_loop_period(eee, nowTime);
} /* while */
#ifdef WIN32
WaitForSingleObject(tun_read_thread, INFINITE);
#endif
send_deregister(eee, &(eee->supernode));
closesocket(eee->udp_sock);
return(0);
}
/* ************************************** */
/** Deinitialise the edge and deallocate any owned memory. */
void edge_term(n2n_edge_t * eee) {
if(eee->udp_sock >= 0)
closesocket(eee->udp_sock);
if(eee->udp_mgmt_sock >= 0)
closesocket(eee->udp_mgmt_sock);
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
if(eee->udp_multicast_sock >= 0)
closesocket(eee->udp_multicast_sock);
#endif
clear_peer_list(&eee->pending_peers);
clear_peer_list(&eee->known_peers);
eee->transop.deinit(&eee->transop);
edge_cleanup_routes(eee);
closeTraceFile();
free(eee);
}
/* ************************************** */
static int edge_init_sockets(n2n_edge_t *eee, int udp_local_port, int mgmt_port, uint8_t tos) {
int sockopt;
if(udp_local_port > 0)
traceEvent(TRACE_NORMAL, "Binding to local port %d", udp_local_port);
eee->udp_sock = open_socket(udp_local_port, 1 /* bind ANY */);
if(eee->udp_sock < 0) {
traceEvent(TRACE_ERROR, "Failed to bind main UDP port %u", udp_local_port);
return(-1);
}
if(tos) {
/* https://www.tucny.com/Home/dscp-tos */
sockopt = tos;
if(setsockopt(eee->udp_sock, IPPROTO_IP, IP_TOS, (char *)&sockopt, sizeof(sockopt)) == 0)
traceEvent(TRACE_NORMAL, "TOS set to 0x%x", tos);
else
traceEvent(TRACE_ERROR, "Could not set TOS 0x%x[%d]: %s", tos, errno, strerror(errno));
}
#ifdef IP_PMTUDISC_DO
sockopt = (eee->conf.disable_pmtu_discovery) ? IP_PMTUDISC_DONT : IP_PMTUDISC_DO;
if(setsockopt(eee->udp_sock, IPPROTO_IP, IP_MTU_DISCOVER, &sockopt, sizeof(sockopt)) < 0)
traceEvent(TRACE_WARNING, "Could not %s PMTU discovery[%d]: %s",
(eee->conf.disable_pmtu_discovery) ? "disable" : "enable", errno, strerror(errno));
else
traceEvent(TRACE_DEBUG, "PMTU discovery %s", (eee->conf.disable_pmtu_discovery) ? "disabled" : "enabled");
#endif
eee->udp_mgmt_sock = open_socket(mgmt_port, 0 /* bind LOOPBACK */);
if(eee->udp_mgmt_sock < 0) {
traceEvent(TRACE_ERROR, "Failed to bind management UDP port %u", mgmt_port);
return(-2);
}
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
/* Populate the multicast group for local edge */
eee->multicast_peer.family = AF_INET;
eee->multicast_peer.port = N2N_MULTICAST_PORT;
eee->multicast_peer.addr.v4[0] = 224; /* N2N_MULTICAST_GROUP */
eee->multicast_peer.addr.v4[1] = 0;
eee->multicast_peer.addr.v4[2] = 0;
eee->multicast_peer.addr.v4[3] = 68;
eee->udp_multicast_sock = open_socket(N2N_MULTICAST_PORT, 1 /* bind ANY */);
if(eee->udp_multicast_sock < 0)
return(-3);
else {
u_int enable_reuse = 1;
/* allow multiple sockets to use the same PORT number */
setsockopt(eee->udp_multicast_sock, SOL_SOCKET, SO_REUSEADDR, (char *)&enable_reuse, sizeof(enable_reuse));
#ifdef SO_REUSEPORT /* no SO_REUSEPORT in Windows / old linux versions */
setsockopt(eee->udp_multicast_sock, SOL_SOCKET, SO_REUSEPORT, &enable_reuse, sizeof(enable_reuse));
#endif
}
#endif
return(0);
}
/* ************************************** */
#ifdef __linux__
static uint32_t get_gateway_ip() {
FILE *fd;
char *token = NULL;
char *gateway_ip_str = NULL;
char buf[256];
uint32_t gateway = 0;
if(!(fd = fopen("/proc/net/route", "r")))
return(0);
while(fgets(buf, sizeof(buf), fd)) {
if(strtok(buf, "\t") && (token = strtok(NULL, "\t")) && (!strcmp(token, "00000000"))) {
token = strtok(NULL, "\t");
if(token) {
struct in_addr addr;
addr.s_addr = strtoul(token, NULL, 16);
gateway_ip_str = inet_ntoa(addr);
if(gateway_ip_str) {
gateway = addr.s_addr;
break;
}
}
}
}
fclose(fd);
return(gateway);
}
static char* route_cmd_to_str(int cmd, const n2n_route_t *route, char *buf, size_t bufsize) {
const char *cmd_str;
struct in_addr addr;
char netbuf[64], gwbuf[64];
switch(cmd) {
case RTM_NEWROUTE:
cmd_str = "Add";
break;
case RTM_DELROUTE:
cmd_str = "Delete";
break;
default:
cmd_str = "?";
}
addr.s_addr = route->net_addr;
inet_ntop(AF_INET, &addr, netbuf, sizeof(netbuf));
addr.s_addr = route->gateway;
inet_ntop(AF_INET, &addr, gwbuf, sizeof(gwbuf));
snprintf(buf, bufsize, "%s %s/%d via %s", cmd_str, netbuf, route->net_bitlen, gwbuf);
return(buf);
}
/* Adapted from https://olegkutkov.me/2019/08/29/modifying-linux-network-routes-using-netlink/ */
#define NLMSG_TAIL(nmsg) \
((struct rtattr *) (((char *) (nmsg)) + NLMSG_ALIGN((nmsg)->nlmsg_len)))
/* Add new data to rtattr */
static int rtattr_add(struct nlmsghdr *n, int maxlen, int type, const void *data, int alen)
{
int len = RTA_LENGTH(alen);
struct rtattr *rta;
if(NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len) > maxlen) {
traceEvent(TRACE_ERROR, "rtattr_add error: message exceeded bound of %d\n", maxlen);
return -1;
}
rta = NLMSG_TAIL(n);
rta->rta_type = type;
rta->rta_len = len;
if(alen)
memcpy(RTA_DATA(rta), data, alen);
n->nlmsg_len = NLMSG_ALIGN(n->nlmsg_len) + RTA_ALIGN(len);
return 0;
}
static int routectl(int cmd, int flags, n2n_route_t *route, int if_idx) {
int rv = -1;
int rv2;
char nl_buf[8192]; /* >= 8192 to avoid truncation, see "man 7 netlink" */
char route_buf[256];
struct iovec iov;
struct msghdr msg;
struct sockaddr_nl sa;
uint8_t read_reply = 1;
int nl_sock;
struct {
struct nlmsghdr n;
struct rtmsg r;
char buf[4096];
} nl_request;
if((nl_sock = socket(AF_NETLINK, SOCK_RAW, NETLINK_ROUTE)) == -1) {
traceEvent(TRACE_ERROR, "netlink socket creation failed [%d]: %s", errno, strerror(errno));
return(-1);
}
/* Subscribe to route change events */
iov.iov_base = nl_buf;
iov.iov_len = sizeof(nl_buf);
memset(&sa, 0, sizeof(sa));
sa.nl_family = PF_NETLINK;
sa.nl_groups = RTMGRP_IPV4_ROUTE | RTMGRP_NOTIFY;
sa.nl_pid = getpid();
memset(&msg, 0, sizeof(msg));
msg.msg_name = &sa;
msg.msg_namelen = sizeof(sa);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
/* Subscribe to route events */
if(bind(nl_sock, (struct sockaddr*)&sa, sizeof(sa)) == -1) {
traceEvent(TRACE_ERROR, "netlink socket bind failed [%d]: %s", errno, strerror(errno));
goto out;
}
/* Initialize request structure */
memset(&nl_request, 0, sizeof(nl_request));
nl_request.n.nlmsg_len = NLMSG_LENGTH(sizeof(struct rtmsg));
nl_request.n.nlmsg_flags = NLM_F_REQUEST | flags;
nl_request.n.nlmsg_type = cmd;
nl_request.r.rtm_family = AF_INET;
nl_request.r.rtm_table = RT_TABLE_MAIN;
nl_request.r.rtm_scope = RT_SCOPE_NOWHERE;
/* Set additional flags if NOT deleting route */
if(cmd != RTM_DELROUTE) {
nl_request.r.rtm_protocol = RTPROT_BOOT;
nl_request.r.rtm_type = RTN_UNICAST;
}
nl_request.r.rtm_family = AF_INET;
nl_request.r.rtm_dst_len = route->net_bitlen;
/* Select scope, for simplicity we supports here only IPv6 and IPv4 */
if(nl_request.r.rtm_family == AF_INET6)
nl_request.r.rtm_scope = RT_SCOPE_UNIVERSE;
else
nl_request.r.rtm_scope = RT_SCOPE_LINK;
/* Set gateway */
if(route->net_bitlen) {
if(rtattr_add(&nl_request.n, sizeof(nl_request), RTA_GATEWAY, &route->gateway, 4) < 0)
goto out;
nl_request.r.rtm_scope = 0;
nl_request.r.rtm_family = AF_INET;
}
/* Don't set destination and interface in case of default gateways */
if(route->net_bitlen) {
/* Set destination network */
if(rtattr_add(&nl_request.n, sizeof(nl_request), /*RTA_NEWDST*/ RTA_DST, &route->net_addr, 4) < 0)
goto out;
/* Set interface */
if(if_idx > 0) {
if(rtattr_add(&nl_request.n, sizeof(nl_request), RTA_OIF, &if_idx, sizeof(int)) < 0)
goto out;
}
}
/* Send message to the netlink */
if((rv2 = send(nl_sock, &nl_request, sizeof(nl_request), 0)) != sizeof(nl_request)) {
traceEvent(TRACE_ERROR, "netlink send failed [%d]: %s", errno, strerror(errno));
goto out;
}
/* Wait for the route notification. Assume that the first reply we get is the correct one. */
traceEvent(TRACE_DEBUG, "waiting for netlink response...");
while(read_reply) {
ssize_t len = recvmsg(nl_sock, &msg, 0);
struct nlmsghdr *nh;
for(nh = (struct nlmsghdr *)nl_buf; NLMSG_OK(nh, len); nh = NLMSG_NEXT(nh, len)) {
/* Stop after the first reply */
read_reply = 0;
if(nh->nlmsg_type == NLMSG_ERROR) {
struct nlmsgerr *err = NLMSG_DATA(nh);
int errcode = err->error;
if(errcode < 0)
errcode = -errcode;
/* Ignore EEXIST as existing rules are ok */
if(errcode != EEXIST) {
traceEvent(TRACE_ERROR, "[err=%d] route: %s", errcode, route_cmd_to_str(cmd, route, route_buf, sizeof(route_buf)));
goto out;
}
}
if(nh->nlmsg_type == NLMSG_DONE)
break;
if(nh->nlmsg_type == cmd) {
traceEvent(TRACE_DEBUG, "Found netlink reply");
break;
}
}
}
traceEvent(TRACE_DEBUG, route_cmd_to_str(cmd, route, route_buf, sizeof(route_buf)));
rv = 0;
out:
close(nl_sock);
return(rv);
}
#endif
/* ************************************** */
static int edge_init_routes_linux(n2n_edge_t *eee, n2n_route_t *routes, uint16_t num_routes) {
#ifdef __linux__
int i;
for (i = 0; i<num_routes; i++) {
n2n_route_t *route = &routes[i];
if ((route->net_addr == 0) && (route->net_bitlen == 0)) {
/* This is a default gateway rule. We need to:
*
* 1. Add a route to the supernode via the host internet gateway
* 2. Add the new default gateway route
*
* Instead of modifying the system default gateway, we use the trick
* of adding a route to the networks 0.0.0.0/1 and 128.0.0.0/1, thus
* covering the whole IPv4 range. Such routes in linux take precedence
* over the default gateway (0.0.0.0/0) since are more specific.
* This leaves the default gateway unchanged so that after n2n is
* stopped the cleanup is easier.
* See https://github.com/zerotier/ZeroTierOne/issues/178#issuecomment-204599227
*/
n2n_sock_t sn;
n2n_route_t custom_route;
uint32_t *a;
if (eee->sn_route_to_clean) {
traceEvent(TRACE_ERROR, "Only one default gateway route allowed");
return(-1);
}
if (eee->conf.sn_num != 1) {
traceEvent(TRACE_ERROR, "Only one supernode supported with routes");
return(-1);
}
if (supernode2addr(&sn, eee->conf.sn_ip_array[0]) < 0)
return(-1);
if (sn.family != AF_INET) {
traceEvent(TRACE_ERROR, "Only IPv4 routes supported");
return(-1);
}
a = (u_int32_t*)sn.addr.v4;
custom_route.net_addr = *a;
custom_route.net_bitlen = 32;
custom_route.gateway = get_gateway_ip();
if (!custom_route.gateway) {
traceEvent(TRACE_ERROR, "could not determine the gateway IP address");
return(-1);
}
/* ip route add supernode via internet_gateway */
if (routectl(RTM_NEWROUTE, NLM_F_CREATE | NLM_F_EXCL, &custom_route, -1) < 0)
return(-1);
/* Save the route to delete it when n2n is stopped */
eee->sn_route_to_clean = calloc(1, sizeof(n2n_route_t));
/* Store a copy of the rules into the runtime to delete it during shutdown */
if (eee->sn_route_to_clean)
*eee->sn_route_to_clean = custom_route;
/* ip route add 0.0.0.0/1 via n2n_gateway */
custom_route.net_addr = 0;
custom_route.net_bitlen = 1;
custom_route.gateway = route->gateway;
if (routectl(RTM_NEWROUTE, NLM_F_CREATE | NLM_F_EXCL, &custom_route, eee->device.if_idx) < 0)
return(-1);
/* ip route add 128.0.0.0/1 via n2n_gateway */
custom_route.net_addr = 128;
custom_route.net_bitlen = 1;
custom_route.gateway = route->gateway;
if (routectl(RTM_NEWROUTE, NLM_F_CREATE | NLM_F_EXCL, &custom_route, eee->device.if_idx) < 0)
return(-1);
}
else {
/* ip route add net via n2n_gateway */
if (routectl(RTM_NEWROUTE, NLM_F_CREATE | NLM_F_EXCL, route, eee->device.if_idx) < 0)
return(-1);
}
}
#endif
return(0);
}
/* ************************************** */
static int edge_init_routes_win(n2n_edge_t *eee, n2n_route_t *routes, uint16_t num_routes)
{
#ifdef WIN32
int i;
struct in_addr net_addr, gateway;
char c_net_addr[32];
char c_gateway[32];
char cmd[256];
for (i = 0; i < num_routes; i++)
{
n2n_route_t *route = &routes[i];
if ((route->net_addr == 0) && (route->net_bitlen == 0))
{
traceEvent(TRACE_NORMAL, "Warning: The 0.0.0.0/0 route settings are not supported on Windows");
return (-1);
}
else
{
/* ip route add net via n2n_gateway */
memcpy(&net_addr, &(route->net_addr), sizeof(net_addr));
memcpy(&gateway, &(route->gateway), sizeof(gateway));
_snprintf(c_net_addr, sizeof(c_net_addr), inet_ntoa(net_addr));
_snprintf(c_gateway, sizeof(c_gateway), inet_ntoa(gateway));
_snprintf(cmd, sizeof(cmd), "route add %s/%d %s > nul", c_net_addr, route->net_bitlen, c_gateway);
traceEvent(TRACE_NORMAL, "ROUTE CMD = '%s'\n", cmd);
system(cmd);
}
}
#endif // WIN32
return (0);
}
/* ************************************** */
/* Add the user-provided routes to the linux routing table. Network routes
* are bound to the n2n TAP device, so they are automatically removed when
* the TAP device is destroyed. */
static int edge_init_routes(n2n_edge_t *eee, n2n_route_t *routes, uint16_t num_routes) {
#ifdef __linux__
return edge_init_routes_linux(eee, routes, num_routes);
#endif
#ifdef WIN32
return edge_init_routes_win(eee, routes, num_routes);
#endif
return 0;
}
/* ************************************** */
static void edge_cleanup_routes(n2n_edge_t *eee) {
#ifdef __linux__
if(eee->sn_route_to_clean) {
/* ip route del supernode via internet_gateway */
routectl(RTM_DELROUTE, 0, eee->sn_route_to_clean, -1);
free(eee->sn_route_to_clean);
}
#endif
}
/* ************************************** */
void edge_init_conf_defaults(n2n_edge_conf_t *conf) {
memset(conf, 0, sizeof(*conf));
conf->local_port = 0 /* any port */;
conf->mgmt_port = N2N_EDGE_MGMT_PORT; /* 5644 by default */
conf->transop_id = N2N_TRANSFORM_ID_NULL;
conf->header_encryption = HEADER_ENCRYPTION_NONE;
conf->compression = N2N_COMPRESSION_ID_NONE;
conf->drop_multicast = 1;
conf->allow_p2p = 1;
conf->disable_pmtu_discovery = 1;
conf->register_interval = REGISTER_SUPER_INTERVAL_DFL;
conf->tuntap_ip_mode = TUNTAP_IP_MODE_SN_ASSIGN;
if (getenv("N2N_KEY")) {
conf->encrypt_key = strdup(getenv("N2N_KEY"));
conf->transop_id = N2N_TRANSFORM_ID_TWOFISH;
}
}
/* ************************************** */
void edge_term_conf(n2n_edge_conf_t *conf) {
if (conf->routes) free(conf->routes);
if (conf->encrypt_key) free(conf->encrypt_key);
}
/* ************************************** */
const n2n_edge_conf_t* edge_get_conf(const n2n_edge_t *eee) {
return(&eee->conf);
}
/* ************************************** */
int edge_conf_add_supernode(n2n_edge_conf_t *conf, const char *ip_and_port) {
if(conf->sn_num >= N2N_EDGE_NUM_SUPERNODES)
return(-1);
strncpy((conf->sn_ip_array[conf->sn_num]), ip_and_port, N2N_EDGE_SN_HOST_SIZE);
traceEvent(TRACE_NORMAL, "Adding supernode[%u] = %s", (unsigned int)conf->sn_num, (conf->sn_ip_array[conf->sn_num]));
conf->sn_num++;
return(0);
}
/* ************************************** */
int quick_edge_init(char *device_name, char *community_name,
char *encrypt_key, char *device_mac,
char *local_ip_address,
char *supernode_ip_address_port,
int *keep_on_running) {
tuntap_dev tuntap;
n2n_edge_t *eee;
n2n_edge_conf_t conf;
int rv;
/* Setup the configuration */
edge_init_conf_defaults(&conf);
conf.encrypt_key = encrypt_key;
conf.transop_id = N2N_TRANSFORM_ID_TWOFISH;
snprintf((char*)conf.community_name, sizeof(conf.community_name), "%s", community_name);
edge_conf_add_supernode(&conf, supernode_ip_address_port);
/* Validate configuration */
if(edge_verify_conf(&conf) != 0)
return(-1);
/* Open the tuntap device */
if(tuntap_open(&tuntap, device_name, "static",
local_ip_address, "255.255.255.0",
device_mac, DEFAULT_MTU) < 0)
return(-2);
/* Init edge */
if((eee = edge_init(&conf, &rv)) == NULL)
goto quick_edge_init_end;
rv = run_edge_loop(eee, keep_on_running);
edge_term(eee);
edge_term_conf(&conf);
quick_edge_init_end:
tuntap_close(&tuntap);
return(rv);
}
/* ************************************** */
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