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message.c
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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"
#ifdef HAVE_MBEDTLS
#include <mbedtls/ssl.h>
#include "dtls.h"
#endif
unsigned char packet_header[4] = {42, 2};
int split_horizon = 1;
unsigned short myseqno = 0;
struct timeval seqno_time = {0, 0};
#define MAX_CHANNEL_HOPS 20
/* Checks whether an AE exists or must be silently ignored */
static int
known_ae(int ae)
{
return ae <= 3;
}
/* 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;
}
normalize_prefix(p_r, prefix, plen < 0 ? 128 : ae == 1 ? plen + 96 : plen);
return ret;
}
static int
parse_update_subtlv(struct interface *ifp, int metric, int ae,
const unsigned char *a, int alen,
unsigned char *channels, int *channels_len_return,
unsigned char *src_prefix, unsigned char *src_plen)
{
int type, len, i = 0;
int channels_len;
int have_src_prefix = 0;
/* This will be overwritten if there's a DIVERSITY_HOPS sub-TLV. */
if(*channels_len_return < 1 || (ifp->flags & IF_FARAWAY)) {
channels_len = 0;
} else {
if(metric < 256) {
/* Assume non-interfering (wired) link. */
channels_len = 0;
} else {
/* Assume interfering. */
channels[0] = IF_CHANNEL_INTERFERING;
channels_len = 1;
}
}
while(i < alen) {
type = a[i];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 2 > alen)
goto fail;
len = a[i + 1];
if(i + len + 2 > alen)
goto fail;
if(type == SUBTLV_PADN) {
/* Nothing. */
} else if(type == SUBTLV_DIVERSITY) {
memcpy(channels, a + i + 2, MIN(len, *channels_len_return));
channels_len = MIN(len, *channels_len_return);
} else if(type == SUBTLV_SOURCE_PREFIX) {
int rc;
if(len < 1)
goto fail;
if(a[i + 2] == 0) /* source prefix cannot be default */
goto fail;
if(have_src_prefix != 0) /* source prefix can only appear once */
goto fail;
rc = network_prefix(ae, a[i + 2], 0, a + i + 3, NULL,
len - 1, src_prefix);
if(rc < 0)
goto fail;
if(ae == 1)
*src_plen = a[i + 2] + 96;
else
*src_plen = a[i + 2];
have_src_prefix = 1;
} else {
debugf("Received unknown%s Update sub-TLV %d.\n",
(type & 0x80) != 0 ? " mandatory" : "", type);
if((type & 0x80) != 0)
return -1;
}
i += len + 2;
}
*channels_len_return = channels_len;
return 1;
fail:
fprintf(stderr, "Received truncated sub-TLV on Update.\n");
return -1;
}
static int
parse_hello_subtlv(const unsigned char *a, int alen,
unsigned int *timestamp_return, int *have_timestamp_return)
{
int type, len, i = 0, have_timestamp = 0;
unsigned int timestamp = 0;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 2 > alen) {
fprintf(stderr, "Received truncated sub-TLV on Hello.\n");
return -1;
}
len = a[i + 1];
if(i + len + 2 > alen) {
fprintf(stderr, "Received truncated sub-TLV on Hello.\n");
return -1;
}
if(type == SUBTLV_PADN) {
/* Nothing to do. */
} else if(type == SUBTLV_TIMESTAMP) {
if(len >= 4) {
DO_NTOHL(timestamp, a + i + 2);
have_timestamp = 1;
} else {
fprintf(stderr,
"Received incorrect RTT sub-TLV on Hello.\n");
/* But don't break. */
}
} else {
debugf("Received unknown%s Hello sub-TLV %d.\n",
(type & 0x80) != 0 ? " mandatory" : "", type);
if((type & 0x80) != 0)
return -1;
}
i += len + 2;
}
if(have_timestamp && timestamp_return)
*timestamp_return = timestamp;
if(have_timestamp_return)
*have_timestamp_return = have_timestamp;
return 1;
}
static int
parse_ihu_subtlv(const unsigned char *a, int alen,
unsigned int *timestamp1_return,
unsigned int *timestamp2_return,
int *have_timestamp_return)
{
int type, len, i = 0;
int have_timestamp = 0;
unsigned int timestamp1, timestamp2;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 2 > alen) {
fprintf(stderr, "Received truncated sub-TLV on IHU.\n");
return -1;
}
len = a[i + 1];
if(i + len + 2 > alen) {
fprintf(stderr, "Received truncated sub-TLV on IHU.\n");
return -1;
}
if(type == SUBTLV_PADN) {
/* Nothing to do. */
} else if(type == SUBTLV_TIMESTAMP) {
if(len >= 8) {
DO_NTOHL(timestamp1, a + i + 2);
DO_NTOHL(timestamp2, a + i + 6);
have_timestamp = 1;
} else {
fprintf(stderr,
"Received incorrect RTT sub-TLV on IHU.\n");
/* But don't break. */
}
} else {
debugf("Received unknown%s IHU sub-TLV %d.\n",
(type & 0x80) != 0 ? " mandatory" : "", type);
if((type & 0x80) != 0)
return -1;
}
i += len + 2;
}
if(have_timestamp && timestamp1_return && timestamp2_return) {
*timestamp1_return = timestamp1;
*timestamp2_return = timestamp2;
}
if(have_timestamp_return) {
*have_timestamp_return = have_timestamp;
}
return 1;
}
static int
parse_request_subtlv(int ae, const unsigned char *a, int alen,
unsigned char *src_prefix, unsigned char *src_plen)
{
int type, len, i = 0;
int have_src_prefix = 0;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 2 > alen)
goto fail;
len = a[i + 1];
if(i + 2 + len > alen)
goto fail;
if(type == SUBTLV_PADN) {
/* Nothing to do. */
} else if(type == SUBTLV_SOURCE_PREFIX) {
int rc;
if(len < 1)
goto fail;
if(a[i + 2] == 0)
goto fail;
if(have_src_prefix != 0)
goto fail;
rc = network_prefix(ae, a[i + 2], 0, a + i + 3, NULL,
len - 1, src_prefix);
if(rc < 0)
goto fail;
if(ae == 1)
*src_plen = a[i + 2] + 96;
else
*src_plen = a[i + 2];
have_src_prefix = 1;
} else {
debugf("Received unknown%s Route Request sub-TLV %d.\n",
((type & 0x80) != 0) ? " mandatory" : "", type);
if((type & 0x80) != 0)
return -1;
}
i += len + 2;
}
return 1;
fail:
fprintf(stderr, "Received truncated sub-TLV on Route Request.\n");
return -1;
}
static int
parse_seqno_request_subtlv(int ae, const unsigned char *a, int alen,
unsigned char *src_prefix, unsigned char *src_plen)
{
int type, len, i = 0;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 2 > alen)
goto fail;
len = a[i + 1];
if(i + len + 2 > alen)
goto fail;
if(type == SUBTLV_PADN) {
/* Nothing to do. */
} else if(type == SUBTLV_SOURCE_PREFIX) {
int rc;
if(len < 1)
goto fail;
*src_plen = a[i + 2];
rc = network_prefix(ae, *src_plen, 0, a + i + 3, NULL,
len - 1, src_prefix);
if(rc < 0)
goto fail;
if(ae == 1)
(*src_plen) += 96;
} else {
debugf("Received unknown%s Route Request sub-TLV %d.\n",
((type & 0x80) != 0) ? " mandatory" : "", type);
if((type & 0x80) != 0)
return -1;
}
i += len + 2;
}
return 1;
fail:
fprintf(stderr, "Received truncated sub-TLV on Route Request.\n");
return -1;
}
static int
parse_other_subtlv(const unsigned char *a, int alen)
{
int type, len, i = 0;
while(i < alen) {
type = a[0];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 2 > alen)
goto fail;
len = a[i + 1];
if(i + 2 + len > alen)
goto fail;
if((type & 0x80) != 0) {
debugf("Received unknown mandatory sub-TLV %d.\n", type);
return -1;
}
i += len + 2;
}
return 1;
fail:
fprintf(stderr, "Received truncated sub-TLV.\n");
return -1;
}
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);
}
void
parse_packet(const unsigned char *from, struct interface *ifp,
const unsigned char *packet, int packetlen,
int ignore)
{
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) != 0) {
/* 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;
}
DO_NTOHS(bodylen, packet + 2);
if(bodylen + 4 > packetlen) {
fprintf(stderr, "Received truncated packet (%d + 4 > %d).\n",
bodylen, packetlen);
bodylen = packetlen - 4;
}
neigh = find_neighbour(from, ifp);
if(neigh == NULL) {
fprintf(stderr, "Couldn't allocate neighbour.\n");
return;
}
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 + 2 > bodylen) {
fprintf(stderr, "Received truncated message.\n");
break;
}
len = message[1];
if(i + len + 2 > bodylen) {
fprintf(stderr, "Received truncated message.\n");
break;
}
if(type == MESSAGE_HELLO) {
unsigned short seqno, interval;
int unicast, changed, have_timestamp, rc;
unsigned int timestamp;
if(len < 6) goto fail;
unicast = !!(message[2] & 0x80);
if(ignore && unicast)
goto done;
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);
/* Sub-TLV handling. */
rc = parse_hello_subtlv(message + 8, len - 6,
×tamp, &have_timestamp);
if(rc < 0)
goto done;
changed =
update_neighbour(neigh,
unicast ? &neigh->uhello : &neigh->hello,
unicast, 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);
if(have_timestamp) {
neigh->hello_send_us = timestamp;
neigh->hello_rtt_receive_time = now;
have_hello_rtt = 1;
}
}
if(ignore)
goto done;
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;
int rc;
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);
rc = parse_other_subtlv(message + 8, len - 6);
if(rc < 0)
goto done;
send_ack(neigh, nonce, interval);
} else if(type == MESSAGE_ACK) {
int rc;
debugf("Received ack from %s on %s.\n",
format_address(from), ifp->name);
rc = parse_other_subtlv(message + 4, len - 2);
if(rc < 0)
goto done;
/* Nothing right now */
} else if(type == MESSAGE_IHU) {
unsigned short txcost, interval;
unsigned char address[16];
int rc;
if(len < 6) goto fail;
if(!known_ae(message[2])) {
debugf("Received IHU with unknown AE %d. Ignoring.\n",
message[2]);
goto done;
}
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;
rc = parse_ihu_subtlv(message + 8 + rc, len - 6 - rc,
&hello_send_us, &hello_rtt_receive_time,
NULL);
if(rc < 0)
goto done;
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);
}
} else if(type == MESSAGE_ROUTER_ID) {
int rc;
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);
rc = parse_other_subtlv(message + 12, len - 10);
if(rc < 0)
goto done;
} 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(!known_ae(message[2])) {
debugf("Received NH with unknown AE %d. Ignoring.\n",
message[2]);
goto done;
}
if(message[2] == 0) {
debugf("Received NH with bad AE 0. Error.\n");
goto fail;
}
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;
}
rc = parse_other_subtlv(message + 4 + rc, len - 2 - rc);
if(rc < 0)
goto done;
} else if(type == MESSAGE_UPDATE) {
unsigned char prefix[16], src_prefix[16], *nh;
unsigned char plen, src_plen;
unsigned char channels[MAX_CHANNEL_HOPS];
int channels_len = MAX_CHANNEL_HOPS;
unsigned short interval, seqno, metric;
int rc, parsed_len, is_ss;
if(len < 10) {
if(len < 2 || message[3] & 0x80)
have_v4_prefix = have_v6_prefix = 0;
goto fail;
}
if(!known_ae(message[2])) {
debugf("Received update with unknown AE %d. Ignoring.\n",
message[2]);
goto done;
}
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(message[2] == 1) {
v4tov6(src_prefix, zeroes);
src_plen = 96;
} else {
memcpy(src_prefix, zeroes, 16);
src_plen = 0;
}
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] == 1) {
if(!have_v4_nh)
goto fail;
nh = v4_nh;
} else if(have_v6_nh) {
nh = v6_nh;
} else {
nh = neigh->address;
}
rc = parse_update_subtlv(ifp, metric, message[2],
message + 2 + parsed_len,
len - parsed_len, channels, &channels_len,
src_prefix, &src_plen);
if(rc < 0)
goto done;
if(message[2] == 0) {
if(metric < 0xFFFF) {
fprintf(stderr,
"Received wildcard update with finite metric.\n");
goto done;
}
if(src_plen > 0) {
fprintf(stderr,
"Received wildcard update with source prefix.\n");
goto done;
}
retract_neighbour_routes(neigh);
goto done;
}
is_ss = !is_default(src_prefix, src_plen);
debugf("Received update%s%s for dst %s%s%s from %s on %s.\n",
(message[3] & 0x80) ? "/prefix" : "",
(message[3] & 0x40) ? "/id" : "",
format_prefix(prefix, plen),
is_ss ? " src " : "",
is_ss ? format_prefix(src_prefix, src_plen) : "",
format_address(from), ifp->name);
if(message[2] == 1) {
if(!ifp->ipv4)
goto done;
}
update_route(router_id, prefix, plen, src_prefix, src_plen, seqno,
metric, interval, neigh, nh,
channels, channels_len);
} else if(type == MESSAGE_REQUEST) {
unsigned char prefix[16], src_prefix[16], plen, src_plen;
int rc, is_ss;
if(len < 2) goto fail;
if(!known_ae(message[2])) {
debugf("Received request with unknown AE %d. Ignoring.\n",
message[2]);
goto done;
}
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);
if(message[2] == 1) {
v4tov6(src_prefix, zeroes);
src_plen = 96;
} else {
memcpy(src_prefix, zeroes, 16);
src_plen = 0;
}
rc = parse_request_subtlv(message[2], message + 4 + rc,
len - 2 - rc, src_prefix, &src_plen);
if(rc < 0)
goto done;
is_ss = !is_default(src_prefix, src_plen);
if(message[2] == 0) {
if(is_ss) {
/* Wildcard requests don't carry a source prefix. */
fprintf(stderr,
"Received source-specific wildcard request.\n");
goto done;
}
debugf("Received request for any from %s on %s.\n",
format_address(from), ifp->name);
/* 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, NULL, 0);
}
} else {
debugf("Received request for dst %s%s%s from %s on %s.\n",
message[2] == 0 ? "" : format_prefix(prefix, plen),
is_ss ? " src " : "",
is_ss ? 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) {
unsigned char prefix[16], src_prefix[16], plen, src_plen;
unsigned short seqno;
int rc, is_ss;
if(len < 14) goto fail;
if(!known_ae(message[2])) {
debugf("Received mh_request with unknown AE %d. Ignoring.\n",
message[2]);
goto done;
}
DO_NTOHS(seqno, message + 4);
rc = network_prefix(message[2], message[3], 0,
message + 16, NULL, len - 14, prefix);
if(rc < 0) goto fail;
if(message[2] == 1) {
v4tov6(src_prefix, zeroes);
src_plen = 96;
} else {
memcpy(src_prefix, zeroes, 16);
src_plen = 0;
}
rc = parse_seqno_request_subtlv(message[2], message + 16 + rc,
len - 14 - rc, src_prefix,
&src_plen);
if(rc < 0)
goto done;
is_ss = !is_default(src_prefix, src_plen);
plen = message[3] + (message[2] == 1 ? 96 : 0);
debugf("Received request (%d) for dst %s%s%s from %s on "
"%s (%s, %d).\n",
message[6],
format_prefix(prefix, plen),
is_ss ? " src " : "",
is_ss ? format_prefix(src_prefix, src_plen) : "",
format_address(from), ifp->name,
format_eui64(message + 8), seqno);
handle_request(neigh, prefix, plen, src_prefix, src_plen,
message[6], seqno, message + 8);
} 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;
}
static int
fill_rtt_message(struct buffered *buf, struct interface *ifp)
{
if((ifp->flags & IF_TIMESTAMPS) != 0 && (buf->hello >= 0)) {
if(buf->buf[buf->hello + 8] == SUBTLV_PADN &&
buf->buf[buf->hello + 9] == 4) {
unsigned int time;
/* Change the type of sub-TLV. */
buf->buf[buf->hello + 8] = SUBTLV_TIMESTAMP;
gettime(&now);
time = time_us(now);
DO_HTONL(buf->buf + buf->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 buffered *buf, struct interface *ifp)
{
int rc;
assert(buf->len <= buf->size);
if(buf->len > 0) {
debugf(" (flushing %d buffered bytes)\n", buf->len);
DO_HTONS(packet_header + 2, buf->len);
fill_rtt_message(buf, ifp);
#ifdef USE_DTLS
/* FIXME: what if we want to send a unicast hello over the
unprotected socket? */
if(buf->dtls != NULL) {
rc = dtls_send(packet_header, sizeof(packet_header),
buf->buf, buf->len,
buf->dtls);
} else {
rc = babel_send(protocol_socket,
packet_header, sizeof(packet_header),
buf->buf, buf->len,
(struct sockaddr*)&buf->sin6,
sizeof(buf->sin6));
}
#else
rc = babel_send(protocol_socket,
packet_header, sizeof(packet_header),
buf->buf, buf->len,
(struct sockaddr*)&buf->sin6,
sizeof(buf->sin6));
#endif
if(rc < 0)
perror("send");
}
VALGRIND_MAKE_MEM_UNDEFINED(buf->buf, buf->size);
buf->len = 0;
buf->hello = -1;
buf->have_id = 0;
buf->have_nh = 0;
buf->have_prefix = 0;