origpkt->len = origlen;
}
-bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
- node_t *to = handle;
+static bool send_sptps_data_priv(node_t *to, node_t *from, int type, const char *data, size_t len) {
+ node_t *relay = (to->via != myself && (type == PKT_PROBE || (len - SPTPS_DATAGRAM_OVERHEAD) <= to->via->minmtu)) ? to->via : to->nexthop;
+ bool direct = from == myself && to == relay;
+ bool relay_supported = (relay->options >> 24) >= 4;
- /* Send it via TCP if it is a handshake packet, TCPOnly is in use, or this packet is larger than the MTU. */
+ /* Send it via TCP if it is a handshake packet, TCPOnly is in use, this is a relay packet that the other node cannot understand, or this packet is larger than the MTU.
+ TODO: When relaying, the original sender does not know the end-to-end PMTU (it only knows the PMTU of the first hop).
+ This can lead to scenarios where large packets are sent over UDP to relay, but then relay has no choice but fall back to TCP. */
- if(type >= SPTPS_HANDSHAKE || ((myself->options | to->options) & OPTION_TCPONLY) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > to->minmtu)) {
+ if(type == SPTPS_HANDSHAKE || ((myself->options | relay->options) & OPTION_TCPONLY) || (!direct && !relay_supported) || (type != PKT_PROBE && (len - SPTPS_DATAGRAM_OVERHEAD) > relay->minmtu)) {
char buf[len * 4 / 3 + 5];
b64encode(data, buf, len);
/* If no valid key is known yet, send the packets using ANS_KEY requests,
to ensure we get to learn the reflexive UDP address. */
- if(!to->status.validkey) {
+ if(from == myself && !to->status.validkey) {
to->incompression = myself->incompression;
- return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, myself->name, to->name, buf, to->incompression);
+ return send_request(to->nexthop->connection, "%d %s %s %s -1 -1 -1 %d", ANS_KEY, from->name, to->name, buf, to->incompression);
} else {
- return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, myself->name, to->name, REQ_SPTPS, buf);
+ return send_request(to->nexthop->connection, "%d %s %s %d %s", REQ_KEY, from->name, to->name, REQ_SPTPS, buf);
}
}
- /* Otherwise, send the packet via UDP */
-
- const sockaddr_t *sa = NULL;
- int sock;
-
- if(to->status.send_locally)
- choose_local_address(to, &sa, &sock);
- if(!sa)
- choose_udp_address(to, &sa, &sock);
-
- bool add_srcid = (to->options >> 24) >= 4;
size_t overhead = 0;
- if (add_srcid) overhead += sizeof myself->id;
+ if(relay_supported) overhead += sizeof to->id + sizeof from->id;
char buf[len + overhead]; char* buf_ptr = buf;
- if(add_srcid) {
- memcpy(buf_ptr, &myself->id, sizeof myself->id); buf_ptr += sizeof myself->id;
+ if(relay_supported) {
+ if(direct) {
+ /* Inform the recipient that this packet was sent directly. */
+ node_id_t nullid = {0};
+ memcpy(buf_ptr, &nullid, sizeof nullid); buf_ptr += sizeof nullid;
+ } else {
+ memcpy(buf_ptr, &to->id, sizeof to->id); buf_ptr += sizeof to->id;
+ }
+ memcpy(buf_ptr, &from->id, sizeof from->id); buf_ptr += sizeof from->id;
+
}
/* TODO: if this copy turns out to be a performance concern, change sptps_send_record() to add some "pre-padding" to the buffer and use that instead */
memcpy(buf_ptr, data, len); buf_ptr += len;
+ const sockaddr_t *sa = NULL;
+ int sock;
+ if(relay->status.send_locally)
+ choose_local_address(relay, &sa, &sock);
+ if(!sa)
+ choose_udp_address(relay, &sa, &sock);
+ logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet from %s (%s) to %s (%s) via %s (%s)", from->name, from->hostname, to->name, to->hostname, relay->name, relay->hostname);
if(sendto(listen_socket[sock].udp.fd, buf, buf_ptr - buf, 0, &sa->sa, SALEN(sa->sa)) < 0 && !sockwouldblock(sockerrno)) {
if(sockmsgsize(sockerrno)) {
// Compensate for SPTPS overhead
len -= SPTPS_DATAGRAM_OVERHEAD;
- if(to->maxmtu >= len)
- to->maxmtu = len - 1;
- if(to->mtu >= len)
- to->mtu = len - 1;
+ if(relay->maxmtu >= len)
+ relay->maxmtu = len - 1;
+ if(relay->mtu >= len)
+ relay->mtu = len - 1;
} else {
- logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", to->name, to->hostname, sockstrerror(sockerrno));
+ logger(DEBUG_TRAFFIC, LOG_WARNING, "Error sending UDP SPTPS packet to %s (%s): %s", relay->name, relay->hostname, sockstrerror(sockerrno));
return false;
}
}
return true;
}
+bool send_sptps_data(void *handle, uint8_t type, const char *data, size_t len) {
+ return send_sptps_data_priv(handle, myself, type, data, len);
+}
+
bool receive_sptps_record(void *handle, uint8_t type, const char *data, uint16_t len) {
node_t *from = handle;
sockaddr_t from = {{0}};
socklen_t fromlen = sizeof from;
node_t *n = NULL;
+ node_t *to = myself;
int len;
- len = recvfrom(ls->udp.fd, &pkt.srcid, MAXSIZE, 0, &from.sa, &fromlen);
+ len = recvfrom(ls->udp.fd, &pkt.dstid, MAXSIZE, 0, &from.sa, &fromlen);
if(len <= 0 || len > MAXSIZE) {
if(!sockwouldblock(sockerrno))
sockaddrunmap(&from); /* Some braindead IPv6 implementations do stupid things. */
- if(len >= sizeof pkt.srcid)
+ bool direct = false;
+ if(len >= sizeof pkt.dstid + sizeof pkt.srcid) {
n = lookup_node_id(&pkt.srcid);
- if(n)
- pkt.len -= sizeof pkt.srcid;
- else {
- /* Most likely an old-style packet without a source ID. */
- memmove(pkt.seqno, &pkt.srcid, sizeof pkt - offsetof(vpn_packet_t, seqno));
+ if(n) {
+ node_id_t nullid = {0};
+ if(memcmp(&pkt.dstid, &nullid, sizeof nullid) == 0) {
+ /* A zero dstid is used to indicate a direct, non-relayed packet. */
+ direct = true;
+ } else {
+ to = lookup_node_id(&pkt.dstid);
+ if(!to) {
+ logger(DEBUG_PROTOCOL, LOG_WARNING, "Received UDP packet presumably sent by %s (%s) but with unknown destination ID", n->name, n->hostname);
+ return;
+ }
+ }
+ pkt.len -= sizeof pkt.dstid + sizeof pkt.srcid;
+ }
+ }
+
+ if(to != myself) {
+ /* We are being asked to relay this packet. */
+
+ /* Don't allow random strangers to relay through us. Note that we check for *any* known address since we are not necessarily the first relay. */
+ if (!lookup_node_udp(&from)) {
+ logger(DEBUG_PROTOCOL, LOG_WARNING, "Refusing to relay packet from (presumably) %s (%s) to (presumably) %s (%s) because the packet comes from an unknown address", n->name, n->hostname, to->name, to->hostname);
+ return;
+ }
+
+ send_sptps_data_priv(to, n, 0, pkt.seqno, pkt.len);
+ return;
+ }
+
+ if(!n) {
+ /* Most likely an old-style packet without node IDs. */
+ direct = true;
+ memmove(pkt.seqno, &pkt.dstid, sizeof pkt - offsetof(vpn_packet_t, seqno));
n = lookup_node_udp(&from);
}
return;
n->sock = ls - listen_socket;
- if(sockaddrcmp(&from, &n->address))
+ if(direct && sockaddrcmp(&from, &n->address))
update_node_udp(n, &from);
}
projects / tinc / blobdiff