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edge_utils.c
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/**
* (C) 2007-18 - 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 "lzoconf.h"
#ifdef WIN32
#include <process.h>
/* Multicast peers discovery disabled due to https://github.com/ntop/n2n/issues/65 */
#define SKIP_MULTICAST_PEERS_DISCOVERY
#endif
#ifdef __ANDROID_NDK__
#include "android/edge_android.h"
#include <tun2tap/tun2tap.h>
#endif /* __ANDROID_NDK__ */
#define SOCKET_TIMEOUT_INTERVAL_SECS 10
#define REGISTER_SUPER_INTERVAL_DFL 20 /* sec, usually UDP NAT entries in a firewall expire after 30 seconds */
#define IFACE_UPDATE_INTERVAL (30) /* sec. How long it usually takes to get an IP lease. */
#define TRANSOP_TICK_INTERVAL (10) /* sec */
#ifdef __ANDROID_NDK__
#define ARP_PERIOD_INTERVAL (10) /* sec */
#endif
#define ETH_FRAMESIZE 14
#define IP4_SRCOFFSET 12
#define IP4_DSTOFFSET 16
#define IP4_MIN_SIZE 20
#define UDP_SIZE 8
/* ************************************** */
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 void 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);
}
/* ************************************** */
struct n2n_edge_stats {
uint32_t tx_p2p;
uint32_t rx_p2p;
uint32_t tx_sup;
uint32_t rx_sup;
uint32_t tx_sup_broadcast;
uint32_t rx_sup_broadcast;
};
/* ************************************** */
struct n2n_edge {
n2n_edge_conf_t conf;
/* Status */
uint8_t sn_idx; /**< Currently active supernode. */
uint8_t sn_wait; /**< Whether we are waiting for a supernode response. */
size_t sup_attempts; /**< Number of remaining attempts to this supernode. */
tuntap_dev device; /**< All about the TUNTAP device */
n2n_trans_op_t transop; /**< The transop to use when encoding */
n2n_cookie_t last_cookie; /**< Cookie sent in last REGISTER_SUPER. */
/* Sockets */
n2n_sock_t supernode;
int udp_sock;
int udp_mgmt_sock; /**< socket for status info. */
#ifndef SKIP_MULTICAST_PEERS_DISCOVERY
n2n_sock_t multicast_peer; /**< Multicast peer group (for local edges) */
int udp_multicast_sock; /**< socket for local multicast registrations. */
int multicast_joined; /**< 1 if the group has been joined.*/
#endif
/* Peers */
struct peer_info * known_peers; /**< Edges we are connected to. */
struct peer_info * pending_peers; /**< Edges we have tried to register with. */
/* Timers */
time_t last_register_req; /**< Check if time to re-register with super*/
time_t last_p2p; /**< Last time p2p traffic was received. */
time_t last_sup; /**< Last time a packet arrived from supernode. */
time_t start_time; /**< For calculating uptime */
/* Statistics */
struct n2n_edge_stats stats;
};
/* ************************************** */
static 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");
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 tuntap_dev *dev, 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));
memcpy(&eee->device, dev, sizeof(*dev));
eee->start_time = time(NULL);
eee->known_peers = NULL;
eee->pending_peers = NULL;
eee->sup_attempts = N2N_EDGE_SUP_ATTEMPTS;
#ifdef NOT_USED
if(lzo_init() != LZO_E_OK) {
traceEvent(TRACE_ERROR, "LZO compression error");
goto edge_init_error;
}
#endif
for(i=0; i<conf->sn_num; ++i)
traceEvent(TRACE_NORMAL, "supernode %u => %s\n", i, (conf->sn_ip_array[i]));
/* Set the active supernode */
supernode2addr(&(eee->supernode), 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
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;
}
if(eee->transop.no_encryption)
traceEvent(TRACE_WARNING, "Encryption is disabled in edge");
if(edge_init_sockets(eee, conf->local_port, conf->mgmt_port, conf->tos) < 0) {
traceEvent(TRACE_ERROR, "Error: socket 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) {
if(((sock->family == AF_INET) && (*((uint32_t*)sock->addr.v4) != htonl(localhost_v4)))
|| ((sock->family == AF_INET6) && memcmp(sock->addr.v6, localhost_v6, IPV6_SIZE)))
return(1);
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 void supernode2addr(n2n_sock_t * sn, const n2n_sn_name_t addrIn) {
n2n_sn_name_t addr;
const char *supernode_host;
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);
}
freeaddrinfo(ainfo); /* free everything allocated by getaddrinfo(). */
ainfo = NULL;
} else {
traceEvent(TRACE_WARNING, "Failed to resolve supernode host %s, assuming numeric", supernode_host);
sn_addr = inet_addr(supernode_host); /* uint32_t */
memcpy(sn->addr.v4, &(sn_addr), IPV4_SIZE);
sn->family=AF_INET;
}
} else
traceEvent(TRACE_WARNING, "Wrong supernode parameter (-l <host:port>)");
}
/* ************************************** */
/***
*
* 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. */
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_NORMAL, "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 n2n_mac_t broadcast_mac = { 0xff, 0xff, 0xff, 0xff, 0xff, 0xff };
/** 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;
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) {
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(®, 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; idx < N2N_COOKIE_SIZE; ++idx)
eee->last_cookie[idx] = rand() % 0xff;
memcpy(reg.cookie, eee->last_cookie, N2N_COOKIE_SIZE);
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, ®);
traceEvent(TRACE_DEBUG, "send REGISTER_SUPER to %s",
sock_to_cstr(sockbuf, supernode));
/* 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" );
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(®, 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, ®);
traceEvent(TRACE_INFO, "Send REGISTER to %s",
sock_to_cstr(sockbuf, remote_peer));
/* 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));
/* 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.
*/
static 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++) {
supernode2addr(&(eee->supernode), eee->conf.sn_ip_array[sn_idx]);
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));
}
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, 6))
++(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;
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 */
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*)ð_payload[ETH_FRAMESIZE + IP4_DSTOFFSET];
u_int8_t *dst_mac = (u_int8_t*)eth_payload;
/* Note: all elements of the_ip are in network order */
if(!memcmp(dst_mac, broadcast_mac, 6))
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"); */
}
}
}
/* 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;