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Move UDP probe reply code into its own function.

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This reduces the level of indentation, and prepares for sending gratuitous type 2 probe replies.
This commit is contained in:
Guus Sliepen 2015-01-11 16:12:57 +01:00
parent f0afde0467
commit 79b6adb489
1 changed files with 63 additions and 59 deletions
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122
src/net_packet.c
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@ -101,75 +101,79 @@ static void udp_probe_timeout_handler(void *data) {
n->maxmtu = MTU;
}
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;
}
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;
}
/* 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;
}
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(!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 (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);
}
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 type %d UDP probe reply %d from %s (%s)", DATA(packet)[0], 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); data += 2;
packet->len = MIN_PROBE_SIZE;
} else {
/* Legacy protocol: n won't understand type 2 probe replies. */
DATA(packet)[0] = 1;
}
/* 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;
/* Temporarily set udp_confirmed, so that the reply is sent
back exactly the way it came in. */
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});
}
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);
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;
}
/* 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 applicable, raise the minimum supported MTU */
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(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 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);
}
}