Try to clarify the new code in net_packet.c a bit.
Mainly by trying to reduce complex if statements, by splitting try_tx() into try_tx_legacy() and try_tx_sptps(), since they don't share a lot of code.
This commit is contained in:
Guus Sliepen
parent
6056f1c13b
commit
0e65326047
1 changed files with 78 additions and 51 deletions
129
src/net_packet.c
129
src/net_packet.c
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@ -948,9 +948,12 @@ static length_t choose_initial_maxmtu(node_t *n) {
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#endif
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}
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// This function tries to determines the MTU of a node.
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// By calling this function repeatedly, n->minmtu will be progressively increased, and at some point, n->mtu will be fixed to n->minmtu.
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// If the MTU is already fixed, this function checks if it can be increased.
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/* This function tries to determines the MTU of a node.
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By calling this function repeatedly, n->minmtu will be progressively
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increased, and at some point, n->mtu will be fixed to n->minmtu. If the MTU
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is already fixed, this function checks if it can be increased.
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*/
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static void try_mtu(node_t *n) {
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if(!(n->options & OPTION_PMTU_DISCOVERY))
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return;
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@ -1046,44 +1049,65 @@ static void try_mtu(node_t *n) {
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n->prev_received = n->received;
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}
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// This function tries to establish a tunnel to a node (or its relay) so that packets can be sent (e.g. get SPTPS keys).
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// If a tunnel is already established, it tries to improve it (e.g. by trying to establish a UDP tunnel instead of TCP).
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// This function makes no guarantees - it is up to the caller to check the node's state to figure out if TCP and/or UDP is usable.
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// By calling this function repeatedly, the tunnel is gradually improved until we hit the wall imposed by the underlying network environment.
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// It is recommended to call this function every time a packet is sent (or intended to be sent) to a node,
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// so that the tunnel keeps improving as packets flow, and then gracefully downgrades itself as it goes idle.
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static void try_tx(node_t *n) {
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/* If n is a TCP-only neighbor, we'll only use "cleartext" PACKET
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messages anyway, so there's no need for SPTPS at all. Otherwise, get the keys. */
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if(n->status.sptps && !(n->connection && ((myself->options | n->options) & OPTION_TCPONLY))) {
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try_sptps(n);
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if (!n->status.validkey)
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return;
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}
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/* These functions try to establish a tunnel to a node (or its relay) so that
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packets can be sent (e.g. exchange keys).
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If a tunnel is already established, it tries to improve it (e.g. by trying
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to establish a UDP tunnel instead of TCP). This function makes no
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guarantees - it is up to the caller to check the node's state to figure out
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if TCP and/or UDP is usable. By calling this function repeatedly, the
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tunnel is gradually improved until we hit the wall imposed by the underlying
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network environment. It is recommended to call this function every time a
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packet is sent (or intended to be sent) to a node, so that the tunnel keeps
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improving as packets flow, and then gracefully downgrades itself as it goes
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idle.
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*/
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node_t *via = (n->via == myself) ? n->nexthop : n->via;
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if((myself->options | via->options) & OPTION_TCPONLY)
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static void try_tx_sptps(node_t *n) {
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/* If n is a TCP-only neighbor, we'll only use "cleartext" PACKET
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messages anyway, so there's no need for SPTPS at all. */
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if(n->connection && ((myself->options | n->options) & OPTION_TCPONLY))
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return;
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if(!n->status.sptps && !via->status.validkey && via->last_req_key + 10 <= now.tv_sec) {
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send_req_key(via);
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via->last_req_key = now.tv_sec;
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} else if(via == n || !n->status.sptps || (via->options >> 24) >= 4) {
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try_udp(via);
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try_mtu(via);
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}
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/* Otherwise, try to do SPTPS authentication with n if necessary. */
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/* If we don't know how to reach "via" yet, then try to reach it through a relay. */
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if(n->status.sptps && !via->status.udp_confirmed && via->nexthop != via && (via->nexthop->options >> 24) >= 4)
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try_tx(via->nexthop);
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try_sptps(n);
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/* Do we need to relay packets? */
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node_t *via = (n->via == myself) ? n->nexthop : n->via;
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/* If the relay doesn't support SPTPS, everything goes via TCP anyway. */
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if((via->options >> 24) < 4)
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return;
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/* If we do have a relay, try everything with that one instead. */
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if(via != n)
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return try_tx_sptps(via);
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try_udp(n);
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try_mtu(n);
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}
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static void try_tx_legacy(node_t *n) {
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/* Check if we already have a key, or request one. */
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if(!n->status.validkey) {
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if(n->last_req_key + 10 <= now.tv_sec) {
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send_req_key(n);
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n->last_req_key = now.tv_sec;
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}
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return;
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}
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try_udp(n);
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try_mtu(n);
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}
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/*
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send a packet to the given vpn ip.
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*/
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void send_packet(node_t *n, vpn_packet_t *packet) {
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node_t *via;
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// If it's for myself, write it to the tun/tap device.
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if(n == myself) {
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if(overwrite_mac)
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@ -1094,44 +1118,47 @@ void send_packet(node_t *n, vpn_packet_t *packet) {
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return;
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}
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logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)",
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packet->len, n->name, n->hostname);
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logger(DEBUG_TRAFFIC, LOG_ERR, "Sending packet of %d bytes to %s (%s)", packet->len, n->name, n->hostname);
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// If the node is not reachable, drop it.
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if(!n->status.reachable) {
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logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable",
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n->name, n->hostname);
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logger(DEBUG_TRAFFIC, LOG_INFO, "Node %s (%s) is not reachable", n->name, n->hostname);
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return;
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}
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// Keep track of packet statistics.
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n->out_packets++;
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n->out_bytes += packet->len;
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// Check if it should be sent as an SPTPS packet.
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if(n->status.sptps) {
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send_sptps_packet(n, packet);
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goto end;
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try_tx_sptps(n);
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return;
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}
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via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
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// Determine which node to actually send it to.
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node_t *via = (packet->priority == -1 || n->via == myself) ? n->nexthop : n->via;
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if(via != n)
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logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet to %s via %s (%s)",
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n->name, via->name, n->via->hostname);
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logger(DEBUG_TRAFFIC, LOG_INFO, "Sending packet to %s via %s (%s)", n->name, via->name, n->via->hostname);
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// Try to send via UDP, unless TCP is forced.
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if(packet->priority == -1 || ((myself->options | via->options) & OPTION_TCPONLY)) {
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if(!send_tcppacket(via->connection, packet))
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terminate_connection(via->connection, true);
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} else
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send_udppacket(via, packet);
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return;
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}
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end:
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/* Try to improve the tunnel.
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Note that we do this *after* we send the packet because sending actual packets take priority
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with regard to the send buffer space and latency. */
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try_tx(n);
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send_udppacket(via, packet);
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try_tx_legacy(via);
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}
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/* Broadcast a packet using the minimum spanning tree */
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void broadcast_packet(const node_t *from, vpn_packet_t *packet) {
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// Always give ourself a copy of the packet.
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if(from != myself)
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