From 79b6adb489dde4ae92207ae7b9146f4e141c946c Mon Sep 17 00:00:00 2001 From: Guus Sliepen Date: Sun, 11 Jan 2015 16:12:57 +0100 Subject: [PATCH] Move UDP probe reply code into its own function. This reduces the level of indentation, and prepares for sending gratuitous type 2 probe replies. --- src/net_packet.c | 122 ++++++++++++++++++++++++----------------------- 1 file changed, 63 insertions(+), 59 deletions(-) diff --git a/src/net_packet.c b/src/net_packet.c index 96f8f10e..52c46e14 100644 --- a/src/net_packet.c +++ b/src/net_packet.c @@ -101,75 +101,79 @@ static void udp_probe_timeout_handler(void *data) { n->maxmtu = MTU; } -static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) { - if(!DATA(packet)[0]) { - /* It's a probe request, send back a reply */ +static void send_udp_probe_reply(node_t *n, vpn_packet_t *packet, length_t len) { + if(!n->status.sptps && !n->status.validkey) { + // But not if we don't have his key. + logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request from %s (%s) but we don't have his key yet", n->name, n->hostname); + return; + } - if(!n->status.sptps && !n->status.validkey) { - // But not if we don't have his key. - logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request from %s (%s) but we don't have his key yet", n->name, n->hostname); - return; - } + logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname); - logger(DEBUG_TRAFFIC, LOG_INFO, "Got UDP probe request %d from %s (%s)", packet->len, n->name, n->hostname); + /* Type 2 probe replies were introduced in protocol 17.3 */ + if ((n->options >> 24) >= 3) { + uint8_t *data = DATA(packet); + *data++ = 2; + uint16_t len16 = htons(len); + memcpy(data, &len16, 2); + packet->len = MIN_PROBE_SIZE; + } else { + /* Legacy protocol: n won't understand type 2 probe replies. */ + DATA(packet)[0] = 1; + } - /* Type 2 probe replies were introduced in protocol 17.3 */ - if ((n->options >> 24) >= 3) { - uint8_t *data = DATA(packet); - *data++ = 2; - uint16_t len16 = htons(len); memcpy(data, &len16, 2); data += 2; - packet->len = MIN_PROBE_SIZE; - } else { - /* Legacy protocol: n won't understand type 2 probe replies. */ - DATA(packet)[0] = 1; - } + /* Temporarily set udp_confirmed, so that the reply is sent + back exactly the way it came in. */ - /* Temporarily set udp_confirmed, so that the reply is sent - back exactly the way it came in. */ + bool udp_confirmed = n->status.udp_confirmed; + n->status.udp_confirmed = true; + send_udppacket(n, packet); + n->status.udp_confirmed = udp_confirmed; +} - bool udp_confirmed = n->status.udp_confirmed; - n->status.udp_confirmed = true; - send_udppacket(n, packet); - n->status.udp_confirmed = udp_confirmed; - } else { - length_t probelen = len; - if (DATA(packet)[0] == 2) { - if (len < 3) - logger(DEBUG_TRAFFIC, LOG_WARNING, "Received invalid (too short) UDP probe reply from %s (%s)", n->name, n->hostname); - else { - uint16_t probelen16; memcpy(&probelen16, DATA(packet) + 1, 2); probelen = ntohs(probelen16); - } - } - logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], probelen, n->name, n->hostname); +static void udp_probe_h(node_t *n, vpn_packet_t *packet, length_t len) { + if(!DATA(packet)[0]) { + /* It's a probe request, send back a reply */ + return send_udp_probe_reply(n, packet, len); + } + + if (DATA(packet)[0] == 2) { + // It's a type 2 probe reply, use the length field inside the packet + uint16_t len16; + memcpy(&len16, DATA(packet) + 1, 2); + len = ntohs(len16); + } - /* It's a valid reply: now we know bidirectional communication - is possible using the address and socket that the reply - packet used. */ - n->status.udp_confirmed = true; + logger(DEBUG_TRAFFIC, LOG_INFO, "Got type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], len, n->name, n->hostname); - if(udp_discovery) { - timeout_del(&n->udp_ping_timeout); - timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0}); - } + /* It's a valid reply: now we know bidirectional communication + is possible using the address and socket that the reply + packet used. */ + n->status.udp_confirmed = true; - if(probelen > n->maxmtu) { - logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname); - n->minmtu = probelen; - n->maxmtu = MTU; - /* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */ - n->mtuprobes = 1; - return; - } else if(n->mtuprobes < 0 && probelen == n->maxmtu) { - /* We got a maxmtu sized packet, confirming the PMTU is still valid. */ - n->mtuprobes = -1; - } + if(udp_discovery) { + timeout_del(&n->udp_ping_timeout); + timeout_add(&n->udp_ping_timeout, &udp_probe_timeout_handler, n, &(struct timeval){udp_discovery_timeout, 0}); + } + + if(len > n->maxmtu) { + logger(DEBUG_TRAFFIC, LOG_INFO, "Increase in PMTU to %s (%s) detected, restarting PMTU discovery", n->name, n->hostname); + n->minmtu = len; + n->maxmtu = MTU; + /* Set mtuprobes to 1 so that try_mtu() doesn't reset maxmtu */ + n->mtuprobes = 1; + return; + } else if(n->mtuprobes < 0 && len == n->maxmtu) { + /* We got a maxmtu sized packet, confirming the PMTU is still valid. */ + n->mtuprobes = -1; + n->mtu_ping_sent = now; + } - /* If applicable, raise the minimum supported MTU */ + /* If applicable, raise the minimum supported MTU */ - if(n->minmtu < probelen) { - n->minmtu = probelen; - try_fix_mtu(n); - } + if(n->minmtu < len) { + n->minmtu = len; + try_fix_mtu(n); } } -- 2.20.1