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message.c
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/*
Copyright (c) 2007, 2008 by Juliusz Chroboczek
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
*/
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <sys/time.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include "babeld.h"
#include "util.h"
#include "net.h"
#include "interface.h"
#include "source.h"
#include "neighbour.h"
#include "route.h"
#include "kernel.h"
#include "xroute.h"
#include "resend.h"
#include "message.h"
#include "configuration.h"
unsigned char packet_header[4] = {42, 2};
int split_horizon = 1;
unsigned short myseqno = 0;
struct timeval seqno_time = {0, 0};
#define UNICAST_BUFSIZE 1024
int unicast_buffered = 0;
unsigned char *unicast_buffer = NULL;
struct neighbour *unicast_neighbour = NULL;
struct timeval unicast_flush_timeout = {0, 0};
static const unsigned char v4prefix[16] =
{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0xFF, 0xFF, 0, 0, 0, 0 };
/* Parse a network prefix, encoded in the somewhat baroque compressed
representation used by Babel. Return the number of bytes parsed. */
static int
network_prefix(int ae, int plen, unsigned int omitted,
const unsigned char *p, const unsigned char *dp,
unsigned int len, unsigned char *p_r)
{
unsigned pb;
unsigned char prefix[16];
int ret = -1;
if(plen >= 0)
pb = (plen + 7) / 8;
else if(ae == 1)
pb = 4;
else
pb = 16;
if(pb > 16)
return -1;
memset(prefix, 0, 16);
switch(ae) {
case 0:
ret = 0;
break;
case 1:
if(omitted > 4 || pb > 4 || (pb > omitted && len < pb - omitted))
return -1;
memcpy(prefix, v4prefix, 12);
if(omitted) {
if(dp == NULL || !v4mapped(dp)) return -1;
memcpy(prefix, dp, 12 + omitted);
}
if(pb > omitted) memcpy(prefix + 12 + omitted, p, pb - omitted);
ret = pb - omitted;
break;
case 2:
if(omitted > 16 || (pb > omitted && len < pb - omitted)) return -1;
if(omitted) {
if(dp == NULL || v4mapped(dp)) return -1;
memcpy(prefix, dp, omitted);
}
if(pb > omitted) memcpy(prefix + omitted, p, pb - omitted);
ret = pb - omitted;
break;
case 3:
if(pb > 8 && len < pb - 8) return -1;
prefix[0] = 0xfe;
prefix[1] = 0x80;
if(pb > 8) memcpy(prefix + 8, p, pb - 8);
ret = pb - 8;
break;
default:
return -1;
}
mask_prefix(p_r, prefix, plen < 0 ? 128 : ae == 1 ? plen + 96 : plen);
return ret;
}
static void
parse_update_subtlv(const unsigned char *a, int alen,
unsigned char *channels)
{
int type, len, i = 0;
while(i < alen) {
type = a[i];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 1 > alen) {
fprintf(stderr, "Received truncated attributes.\n");
return;
}
len = a[i + 1];
if(i + len > alen) {
fprintf(stderr, "Received truncated attributes.\n");
return;
}
if(type == SUBTLV_PADN) {
/* Nothing. */
} else if(type == SUBTLV_DIVERSITY) {
if(len > DIVERSITY_HOPS) {
fprintf(stderr,
"Received overlong channel information (%d > %d).\n",
len, DIVERSITY_HOPS);
len = DIVERSITY_HOPS;
}
if(memchr(a + i + 2, 0, len) != NULL) {
/* 0 is reserved. */
fprintf(stderr, "Channel information contains 0!");
return;
}
memset(channels, 0, DIVERSITY_HOPS);
memcpy(channels, a + i + 2, len);
} else {
debugf("Received unknown update sub-TLV %d.\n", type);
}
i += len + 2;
}
}
static int
parse_hello_subtlv(const unsigned char *a, int alen,
unsigned int *hello_send_us)
{
int type, len, i = 0, ret = 0;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 1 > alen) {
fprintf(stderr, "Received truncated sub-TLV on Hello message.\n");
return -1;
}
len = a[i + 1];
if(i + len > alen) {
fprintf(stderr, "Received truncated sub-TLV on Hello message.\n");
return -1;
}
if(type == SUBTLV_PADN) {
/* Nothing to do. */
} else if(type == SUBTLV_TIMESTAMP) {
if(len >= 4) {
DO_NTOHL(*hello_send_us, a + i + 2);
ret = 1;
} else {
fprintf(stderr,
"Received incorrect RTT sub-TLV on Hello message.\n");
}
} else {
debugf("Received unknown Hello sub-TLV type %d.\n", type);
}
i += len + 2;
}
return ret;
}
static int
parse_ihu_subtlv(const unsigned char *a, int alen,
unsigned int *hello_send_us,
unsigned int *hello_rtt_receive_time)
{
int type, len, i = 0, ret = 0;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 1 > alen) {
fprintf(stderr, "Received truncated sub-TLV on IHU message.\n");
return -1;
}
len = a[i + 1];
if(i + len > alen) {
fprintf(stderr, "Received truncated sub-TLV on IHU message.\n");
return -1;
}
if(type == SUBTLV_PADN) {
/* Nothing to do. */
} else if(type == SUBTLV_TIMESTAMP) {
if(len >= 8) {
DO_NTOHL(*hello_send_us, a + i + 2);
DO_NTOHL(*hello_rtt_receive_time, a + i + 6);
ret = 1;
}
else {
fprintf(stderr,
"Received incorrect RTT sub-TLV on IHU message.\n");
}
} else {
debugf("Received unknown IHU sub-TLV type %d.\n", type);
}
i += len + 2;
}
return ret;
}
static int
network_address(int ae, const unsigned char *a, unsigned int len,
unsigned char *a_r)
{
return network_prefix(ae, -1, 0, a, NULL, len, a_r);
}
static int
channels_len(unsigned char *channels)
{
unsigned char *p = memchr(channels, 0, DIVERSITY_HOPS);
return p ? (p - channels) : DIVERSITY_HOPS;
}
void
parse_packet(const unsigned char *from, struct interface *ifp,
const unsigned char *packet, int packetlen)
{
int i;
const unsigned char *message;
unsigned char type, len;
int bodylen;
struct neighbour *neigh;
int have_router_id = 0, have_v4_prefix = 0, have_v6_prefix = 0,
have_v4_nh = 0, have_v6_nh = 0;
unsigned char router_id[8], v4_prefix[16], v6_prefix[16],
v4_nh[16], v6_nh[16];
int have_hello_rtt = 0;
/* Content of the RTT sub-TLV on IHU messages. */
unsigned int hello_send_us = 0, hello_rtt_receive_time = 0;
if(ifp->flags & IF_TIMESTAMPS) {
/* We want to track exactly when we received this packet. */
gettime(&now);
}
if(!linklocal(from)) {
fprintf(stderr, "Received packet from non-local address %s.\n",
format_address(from));
return;
}
if(packet[0] != 42) {
fprintf(stderr, "Received malformed packet on %s from %s.\n",
ifp->name, format_address(from));
return;
}
if(packet[1] != 2) {
fprintf(stderr,
"Received packet with unknown version %d on %s from %s.\n",
packet[1], ifp->name, format_address(from));
return;
}
neigh = find_neighbour(from, ifp);
if(neigh == NULL) {
fprintf(stderr, "Couldn't allocate neighbour.\n");
return;
}
DO_NTOHS(bodylen, packet + 2);
if(bodylen + 4 > packetlen) {
fprintf(stderr, "Received truncated packet (%d + 4 > %d).\n",
bodylen, packetlen);
bodylen = packetlen - 4;
}
i = 0;
while(i < bodylen) {
message = packet + 4 + i;
type = message[0];
if(type == MESSAGE_PAD1) {
debugf("Received pad1 from %s on %s.\n",
format_address(from), ifp->name);
i++;
continue;
}
if(i + 1 > bodylen) {
fprintf(stderr, "Received truncated message.\n");
break;
}
len = message[1];
if(i + len > bodylen) {
fprintf(stderr, "Received truncated message.\n");
break;
}
if(type == MESSAGE_PADN) {
debugf("Received pad%d from %s on %s.\n",
len, format_address(from), ifp->name);
} else if(type == MESSAGE_ACK_REQ) {
unsigned short nonce, interval;
if(len < 6) goto fail;
DO_NTOHS(nonce, message + 4);
DO_NTOHS(interval, message + 6);
debugf("Received ack-req (%04X %d) from %s on %s.\n",
nonce, interval, format_address(from), ifp->name);
send_ack(neigh, nonce, interval);
} else if(type == MESSAGE_ACK) {
debugf("Received ack from %s on %s.\n",
format_address(from), ifp->name);
/* Nothing right now */
} else if(type == MESSAGE_HELLO) {
unsigned short seqno, interval;
int changed;
unsigned int timestamp;
if(len < 6) goto fail;
DO_NTOHS(seqno, message + 4);
DO_NTOHS(interval, message + 6);
debugf("Received hello %d (%d) from %s on %s.\n",
seqno, interval,
format_address(from), ifp->name);
changed = update_neighbour(neigh, seqno, interval);
update_neighbour_metric(neigh, changed);
if(interval > 0)
/* Multiply by 3/2 to allow hellos to expire. */
schedule_neighbours_check(interval * 15, 0);
/* Sub-TLV handling. */
if(len > 8) {
if(parse_hello_subtlv(message + 8, len - 6, ×tamp) > 0) {
neigh->hello_send_us = timestamp;
neigh->hello_rtt_receive_time = now;
have_hello_rtt = 1;
}
}
} else if(type == MESSAGE_IHU) {
unsigned short txcost, interval;
unsigned char address[16];
int rc;
if(len < 6) goto fail;
DO_NTOHS(txcost, message + 4);
DO_NTOHS(interval, message + 6);
rc = network_address(message[2], message + 8, len - 6, address);
if(rc < 0) goto fail;
debugf("Received ihu %d (%d) from %s on %s for %s.\n",
txcost, interval,
format_address(from), ifp->name,
format_address(address));
if(message[2] == 0 || interface_ll_address(ifp, address)) {
int changed = txcost != neigh->txcost;
neigh->txcost = txcost;
neigh->ihu_time = now;
neigh->ihu_interval = interval;
update_neighbour_metric(neigh, changed);
if(interval > 0)
/* Multiply by 3/2 to allow neighbours to expire. */
schedule_neighbours_check(interval * 45, 0);
/* RTT sub-TLV. */
if(len > 10 + rc)
parse_ihu_subtlv(message + 8 + rc, len - 6 - rc,
&hello_send_us, &hello_rtt_receive_time);
}
} else if(type == MESSAGE_ROUTER_ID) {
if(len < 10) {
have_router_id = 0;
goto fail;
}
memcpy(router_id, message + 4, 8);
have_router_id = 1;
debugf("Received router-id %s from %s on %s.\n",
format_eui64(router_id), format_address(from), ifp->name);
} else if(type == MESSAGE_NH) {
unsigned char nh[16];
int rc;
if(len < 2) {
have_v4_nh = 0;
have_v6_nh = 0;
goto fail;
}
rc = network_address(message[2], message + 4, len - 2,
nh);
if(rc < 0) {
have_v4_nh = 0;
have_v6_nh = 0;
goto fail;
}
debugf("Received nh %s (%d) from %s on %s.\n",
format_address(nh), message[2],
format_address(from), ifp->name);
if(message[2] == 1) {
memcpy(v4_nh, nh, 16);
have_v4_nh = 1;
} else {
memcpy(v6_nh, nh, 16);
have_v6_nh = 1;
}
} else if(type == MESSAGE_UPDATE) {
unsigned char prefix[16], *nh;
unsigned char plen;
unsigned char channels[DIVERSITY_HOPS];
unsigned short interval, seqno, metric;
int rc, parsed_len;
if(len < 10) {
if(len < 2 || message[3] & 0x80)
have_v4_prefix = have_v6_prefix = 0;
goto fail;
}
DO_NTOHS(interval, message + 6);
DO_NTOHS(seqno, message + 8);
DO_NTOHS(metric, message + 10);
if(message[5] == 0 ||
(message[2] == 1 ? have_v4_prefix : have_v6_prefix))
rc = network_prefix(message[2], message[4], message[5],
message + 12,
message[2] == 1 ? v4_prefix : v6_prefix,
len - 10, prefix);
else
rc = -1;
if(rc < 0) {
if(message[3] & 0x80)
have_v4_prefix = have_v6_prefix = 0;
goto fail;
}
parsed_len = 10 + rc;
plen = message[4] + (message[2] == 1 ? 96 : 0);
if(message[3] & 0x80) {
if(message[2] == 1) {
memcpy(v4_prefix, prefix, 16);
have_v4_prefix = 1;
} else {
memcpy(v6_prefix, prefix, 16);
have_v6_prefix = 1;
}
}
if(message[3] & 0x40) {
if(message[2] == 1) {
memset(router_id, 0, 4);
memcpy(router_id + 4, prefix + 12, 4);
} else {
memcpy(router_id, prefix + 8, 8);
}
have_router_id = 1;
}
if(!have_router_id && message[2] != 0) {
fprintf(stderr, "Received prefix with no router id.\n");
goto fail;
}
debugf("Received update%s%s for %s from %s on %s.\n",
(message[3] & 0x80) ? "/prefix" : "",
(message[3] & 0x40) ? "/id" : "",
format_prefix(prefix, plen),
format_address(from), ifp->name);
if(message[2] == 0) {
if(metric < 0xFFFF) {
fprintf(stderr,
"Received wildcard update with finite metric.\n");
goto done;
}
retract_neighbour_routes(neigh);
goto done;
} else if(message[2] == 1) {
if(!have_v4_nh)
goto fail;
nh = v4_nh;
} else if(have_v6_nh) {
nh = v6_nh;
} else {
nh = neigh->address;
}
if(message[2] == 1) {
if(!ifp->ipv4)
goto done;
}
if((ifp->flags & IF_FARAWAY)) {
channels[0] = 0;
} else {
/* This will be overwritten by parse_update_subtlv below. */
if(metric < 256) {
/* Assume non-interfering (wired) link. */
channels[0] = 0;
} else {
/* Assume interfering. */
channels[0] = IF_CHANNEL_INTERFERING;
channels[1] = 0;
}
if(parsed_len < len)
parse_update_subtlv(message + 2 + parsed_len,
len - parsed_len, channels);
}
update_route(router_id, prefix, plen, zeroes, 0, seqno,
metric, interval, neigh, nh,
channels, channels_len(channels));
} else if(type == MESSAGE_REQUEST) {
unsigned char prefix[16], plen;
int rc;
if(len < 2) goto fail;
rc = network_prefix(message[2], message[3], 0,
message + 4, NULL, len - 2, prefix);
if(rc < 0) goto fail;
plen = message[3] + (message[2] == 1 ? 96 : 0);
debugf("Received request for %s from %s on %s.\n",
message[2] == 0 ? "any" : format_prefix(prefix, plen),
format_address(from), ifp->name);
if(message[2] == 0) {
/* If a neighbour is requesting a full route dump from us,
we might as well send it an IHU. */
send_ihu(neigh, NULL);
/* Since nodes send wildcard requests on boot, booting
a large number of nodes at the same time may cause an
update storm. Ignore a wildcard request that happens
shortly after we sent a full update. */
if(neigh->ifp->last_update_time <
now.tv_sec - MAX(neigh->ifp->hello_interval / 100, 1))
send_update(neigh->ifp, 0, NULL, 0, zeroes, 0);
} else {
send_update(neigh->ifp, 0, prefix, plen, zeroes, 0);
}
} else if(type == MESSAGE_MH_REQUEST) {
unsigned char prefix[16], plen;
unsigned short seqno;
int rc;
if(len < 14) goto fail;
DO_NTOHS(seqno, message + 4);
rc = network_prefix(message[2], message[3], 0,
message + 16, NULL, len - 14, prefix);
if(rc < 0) goto fail;
plen = message[3] + (message[2] == 1 ? 96 : 0);
debugf("Received request (%d) for %s from %s on %s (%s, %d).\n",
message[6],
format_prefix(prefix, plen),
format_address(from), ifp->name,
format_eui64(message + 8), seqno);
handle_request(neigh, prefix, plen, zeroes, 0, message[6],
seqno, message + 8);
} else if(type == MESSAGE_UPDATE_SRC_SPECIFIC) {
unsigned char prefix[16], src_prefix[16], *nh;
unsigned char ae, plen, src_plen, omitted;
unsigned char channels[DIVERSITY_HOPS];
unsigned short interval, seqno, metric;
const unsigned char *src_prefix_beginning = NULL;
int rc, parsed_len = 0;
if(len < 10)
goto fail;
ae = message[2];
src_plen = message[3];
plen = message[4];
omitted = message[5];
DO_NTOHS(interval, message + 6);
DO_NTOHS(seqno, message + 8);
DO_NTOHS(metric, message + 10);
if(omitted == 0 || (ae == 1 ? have_v4_prefix : have_v6_prefix))
rc = network_prefix(ae, plen, omitted, message + 12,
ae == 1 ? v4_prefix : v6_prefix,
len - 10, prefix);
else
rc = -1;
if(rc < 0)
goto fail;
parsed_len = 10 + rc;
src_prefix_beginning = message + 2 + parsed_len;
rc = network_prefix(ae, src_plen, 0, src_prefix_beginning, NULL,
len - parsed_len, src_prefix);
if(rc < 0)
goto fail;
parsed_len += rc;
if(ae == 1) {
plen += 96;
src_plen += 96;
}
if(!have_router_id) {
fprintf(stderr, "Received prefix with no router id.\n");
goto fail;
}
debugf("Received ss-update for (%s from %s) from %s on %s.\n",
format_prefix(prefix, plen),
format_prefix(src_prefix, src_plen),
format_address(from), ifp->name);
if(ae == 0) {
debugf("Received invalid Source-Specific wildcard update.\n");
retract_neighbour_routes(neigh);
goto done;
} else if(ae == 1) {
if(!have_v4_nh)
goto fail;
nh = v4_nh;
} else if(have_v6_nh) {
nh = v6_nh;
} else {
nh = neigh->address;
}
if(ae == 1) {
if(!ifp->ipv4)
goto done;
}
if((ifp->flags & IF_FARAWAY)) {
channels[0] = 0;
} else {
/* This will be overwritten by parse_update_subtlv below. */
if(metric < 256) {
/* Assume non-interfering (wired) link. */
channels[0] = 0;
} else {
/* Assume interfering. */
channels[0] = IF_CHANNEL_INTERFERING;
channels[1] = 0;
}
if(parsed_len < len)
parse_update_subtlv(message + 2 + parsed_len,
len - parsed_len, channels);
}
update_route(router_id, prefix, plen, src_prefix, src_plen,
seqno, metric, interval, neigh, nh,
channels, channels_len(channels));
} else if(type == MESSAGE_REQUEST_SRC_SPECIFIC) {
unsigned char prefix[16], plen, ae, src_prefix[16], src_plen;
int rc, parsed = 5;
if(len < 3) goto fail;
ae = message[2];
plen = message[3];
src_plen = message[4];
rc = network_prefix(ae, plen, 0, message + parsed,
NULL, len + 2 - parsed, prefix);
if(rc < 0) goto fail;
if(ae == 1)
plen += 96;
parsed += rc;
rc = network_prefix(ae, src_plen, 0, message + parsed,
NULL, len + 2 - parsed, src_prefix);
if(rc < 0) goto fail;
if(ae == 1)
src_plen += 96;
parsed += rc;
if(ae == 0) {
debugf("Received request for any source-specific "
"from %s on %s.\n",
format_address(from), ifp->name);
/* See comments for std requests. */
send_ihu(neigh, NULL);
if(neigh->ifp->last_specific_update_time <
now.tv_sec - MAX(neigh->ifp->hello_interval / 100, 1))
send_update(neigh->ifp, 0, zeroes, 0, NULL, 0);
} else {
debugf("Received request for (%s from %s) from %s on %s.\n",
format_prefix(prefix, plen),
format_prefix(src_prefix, src_plen),
format_address(from), ifp->name);
send_update(neigh->ifp, 0, prefix, plen, src_prefix, src_plen);
}
} else if(type == MESSAGE_MH_REQUEST_SRC_SPECIFIC) {
unsigned char prefix[16], plen, ae, src_prefix[16], src_plen, hopc;
const unsigned char *router_id;
unsigned short seqno;
int rc, parsed = 16;
if(len < 14) goto fail;
ae = message[2];
plen = message[3];
DO_NTOHS(seqno, message + 4);
hopc = message[6];
src_plen = message[7];
router_id = message + 8;
rc = network_prefix(ae, plen, 0, message + parsed,
NULL, len + 2 - parsed, prefix);
if(rc < 0) goto fail;
if(ae == 1)
plen += 96;
parsed += rc;
rc = network_prefix(ae, src_plen, 0, message + parsed,
NULL, len + 2 - parsed, src_prefix);
if(rc < 0) goto fail;
if(ae == 1)
src_plen += 96;
debugf("Received request (%d) for (%s, %s)"
" from %s on %s (%s, %d).\n",
message[6],
format_prefix(prefix, plen),
format_prefix(src_prefix, src_plen),
format_address(from), ifp->name,
format_eui64(router_id), seqno);
handle_request(neigh, prefix, plen, src_prefix, src_plen,
hopc, seqno, router_id);
} else {
debugf("Received unknown packet type %d from %s on %s.\n",
type, format_address(from), ifp->name);
}
done:
i += len + 2;
continue;
fail:
fprintf(stderr, "Couldn't parse packet (%d, %d) from %s on %s.\n",
message[0], message[1], format_address(from), ifp->name);
goto done;
}
/* We can calculate the RTT to this neighbour. */
if(have_hello_rtt && hello_send_us && hello_rtt_receive_time) {
int remote_waiting_us, local_waiting_us;
unsigned int rtt, smoothed_rtt;
unsigned int old_rttcost;
int changed = 0;
remote_waiting_us = neigh->hello_send_us - hello_rtt_receive_time;
local_waiting_us = time_us(neigh->hello_rtt_receive_time) -
hello_send_us;
/* Sanity checks (validity window of 10 minutes). */
if(remote_waiting_us < 0 || local_waiting_us < 0 ||
remote_waiting_us > 600000000 || local_waiting_us > 600000000)
return;
rtt = MAX(0, local_waiting_us - remote_waiting_us);
debugf("RTT to %s on %s sample result: %d us.\n",
format_address(from), ifp->name, rtt);
old_rttcost = neighbour_rttcost(neigh);
if(valid_rtt(neigh)) {
/* Running exponential average. */
smoothed_rtt = (ifp->rtt_decay * rtt +
(256 - ifp->rtt_decay) * neigh->rtt);
/* Rounding (up or down) to get closer to the sample. */
neigh->rtt = (neigh->rtt >= rtt) ? smoothed_rtt / 256 :
(smoothed_rtt + 255) / 256;
} else {
/* We prefer to be conservative with new neighbours
(higher RTT) */
assert(rtt <= 0x7FFFFFFF);
neigh->rtt = 2*rtt;
}
changed = (neighbour_rttcost(neigh) == old_rttcost ? 0 : 1);
update_neighbour_metric(neigh, changed);
neigh->rtt_time = now;
}
return;
}
/* Under normal circumstances, there are enough moderation mechanisms
elsewhere in the protocol to make sure that this last-ditch check
should never trigger. But I'm superstitious. */
static int
check_bucket(struct interface *ifp)
{
if(ifp->bucket <= 0) {
int seconds = now.tv_sec - ifp->bucket_time;
if(seconds > 0) {
ifp->bucket = MIN(BUCKET_TOKENS_MAX,
seconds * BUCKET_TOKENS_PER_SEC);
}
/* Reset bucket time unconditionally, in case clock is stepped. */
ifp->bucket_time = now.tv_sec;
}
if(ifp->bucket > 0) {
ifp->bucket--;
return 1;
} else {
return 0;
}
}
static int
fill_rtt_message(struct interface *ifp)
{
if((ifp->flags & IF_TIMESTAMPS) && (ifp->buffered_hello >= 0)) {
if(ifp->sendbuf[ifp->buffered_hello + 8] == SUBTLV_PADN &&
ifp->sendbuf[ifp->buffered_hello + 9] == 4) {
unsigned int time;
/* Change the type of sub-TLV. */
ifp->sendbuf[ifp->buffered_hello + 8] = SUBTLV_TIMESTAMP;
gettime(&now);
time = time_us(now);
DO_HTONL(ifp->sendbuf + ifp->buffered_hello + 10, time);
return 1;
} else {
fprintf(stderr,
"No space left for timestamp sub-TLV "
"(this shouldn't happen)\n");
return -1;
}
}
return 0;
}
void
flushbuf(struct interface *ifp)
{
int rc;
struct sockaddr_in6 sin6;
assert(ifp->buffered <= ifp->bufsize);
flushupdates(ifp);
if(ifp->buffered > 0) {
debugf(" (flushing %d buffered bytes on %s)\n",
ifp->buffered, ifp->name);
if(check_bucket(ifp)) {
memset(&sin6, 0, sizeof(sin6));
sin6.sin6_family = AF_INET6;
memcpy(&sin6.sin6_addr, protocol_group, 16);
sin6.sin6_port = htons(protocol_port);
sin6.sin6_scope_id = ifp->ifindex;
DO_HTONS(packet_header + 2, ifp->buffered);
fill_rtt_message(ifp);
rc = babel_send(protocol_socket,
packet_header, sizeof(packet_header),
ifp->sendbuf, ifp->buffered,
(struct sockaddr*)&sin6, sizeof(sin6));
if(rc < 0)
perror("send");
} else {
fprintf(stderr, "Warning: bucket full, dropping packet to %s.\n",
ifp->name);
}
}
VALGRIND_MAKE_MEM_UNDEFINED(ifp->sendbuf, ifp->bufsize);
ifp->buffered = 0;
ifp->buffered_hello = -1;
ifp->have_buffered_id = 0;
ifp->have_buffered_nh = 0;
ifp->have_buffered_prefix = 0;
ifp->flush_timeout.tv_sec = 0;
ifp->flush_timeout.tv_usec = 0;
}
static void
schedule_flush(struct interface *ifp)
{
unsigned msecs = jitter(ifp, 0);
if(ifp->flush_timeout.tv_sec != 0 &&
timeval_minus_msec(&ifp->flush_timeout, &now) < msecs)
return;
set_timeout(&ifp->flush_timeout, msecs);
}
static void
schedule_flush_now(struct interface *ifp)
{
/* Almost now */
unsigned msecs = roughly(10);
if(ifp->flush_timeout.tv_sec != 0 &&
timeval_minus_msec(&ifp->flush_timeout, &now) < msecs)
return;
set_timeout(&ifp->flush_timeout, msecs);
}
static void
schedule_unicast_flush(unsigned msecs)
{
if(!unicast_neighbour)
return;
if(unicast_flush_timeout.tv_sec != 0 &&
timeval_minus_msec(&unicast_flush_timeout, &now) < msecs)
return;
unicast_flush_timeout.tv_usec = (now.tv_usec + msecs * 1000) % 1000000;
unicast_flush_timeout.tv_sec =
now.tv_sec + (now.tv_usec / 1000 + msecs) / 1000;
}
static void
ensure_space(struct interface *ifp, int space)
{
if(ifp->bufsize - ifp->buffered < space)
flushbuf(ifp);
}
static void
start_message(struct interface *ifp, int type, int len)
{
if(ifp->bufsize - ifp->buffered < len + 2)
flushbuf(ifp);
ifp->sendbuf[ifp->buffered++] = type;
ifp->sendbuf[ifp->buffered++] = len;
}
static void
end_message(struct interface *ifp, int type, int bytes)
{
assert(ifp->buffered >= bytes + 2 &&
ifp->sendbuf[ifp->buffered - bytes - 2] == type &&
ifp->sendbuf[ifp->buffered - bytes - 1] == bytes);
schedule_flush(ifp);
}
static void
accumulate_byte(struct interface *ifp, unsigned char value)
{
ifp->sendbuf[ifp->buffered++] = value;
}
static void
accumulate_short(struct interface *ifp, unsigned short value)
{
DO_HTONS(ifp->sendbuf + ifp->buffered, value);
ifp->buffered += 2;
}
static void
accumulate_int(struct interface *ifp, unsigned int value)
{
DO_HTONL(ifp->sendbuf + ifp->buffered, value);
ifp->buffered += 4;
}
static void
accumulate_bytes(struct interface *ifp,
const unsigned char *value, unsigned len)
{
memcpy(ifp->sendbuf + ifp->buffered, value, len);
ifp->buffered += len;
}
static int
start_unicast_message(struct neighbour *neigh, int type, int len)
{
if(unicast_neighbour) {
if(neigh != unicast_neighbour ||
unicast_buffered + len + 2 >=
MIN(UNICAST_BUFSIZE, neigh->ifp->bufsize))
flush_unicast(0);
}
if(!unicast_buffer)
unicast_buffer = malloc(UNICAST_BUFSIZE);
if(!unicast_buffer) {
perror("malloc(unicast_buffer)");
return -1;
}
unicast_neighbour = neigh;
unicast_buffer[unicast_buffered++] = type;
unicast_buffer[unicast_buffered++] = len;
return 1;
}
static void
end_unicast_message(struct neighbour *neigh, int type, int bytes)
{
assert(unicast_neighbour == neigh && unicast_buffered >= bytes + 2 &&