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message.c
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// SPDX-License-Identifier: MIT
/*
Copyright (c) 2007, 2008 by Juliusz Chroboczek
*/
#include <zebra.h>
#include "if.h"
#include "babeld.h"
#include "util.h"
#include "net.h"
#include "babel_interface.h"
#include "source.h"
#include "neighbour.h"
#include "route.h"
#include "xroute.h"
#include "resend.h"
#include "message.h"
#include "kernel.h"
#include "babel_main.h"
#include "babel_errors.h"
static unsigned char packet_header[4] = {42, 2};
int split_horizon = 1;
unsigned short myseqno = 0;
#define UNICAST_BUFSIZE 1024
static int unicast_buffered = 0;
static unsigned char *unicast_buffer = NULL;
struct neighbour *unicast_neighbour = NULL;
struct timeval unicast_flush_timeout = {0, 0};
/* Minimum TLV _body_ length for TLVs of particular types (0 = no limit). */
static const unsigned char tlv_min_length[MESSAGE_MAX + 1] =
{
[ MESSAGE_PAD1 ] = 0,
[ MESSAGE_PADN ] = 0,
[ MESSAGE_ACK_REQ ] = 6,
[ MESSAGE_ACK ] = 2,
[ MESSAGE_HELLO ] = 6,
[ MESSAGE_IHU ] = 6,
[ MESSAGE_ROUTER_ID ] = 10,
[ MESSAGE_NH ] = 2,
[ MESSAGE_UPDATE ] = 10,
[ MESSAGE_REQUEST ] = 2,
[ MESSAGE_MH_REQUEST ] = 14,
};
/* Checks whether an AE exists or must be silently ignored */
static bool
known_ae(int ae)
{
return ae <= 4;
}
/* 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 bool 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) {
flog_err(EC_BABEL_PACKET, "Received truncated attributes.");
return false;
}
len = a[i + 1];
if(i + len + 2 > alen) {
flog_err(EC_BABEL_PACKET, "Received truncated attributes.");
return false;
}
if (CHECK_FLAG(type, SUBTLV_MANDATORY)) {
/*
* RFC 8966 - 4.4
* If the mandatory bit is set, then the whole enclosing
* TLV MUST be silently ignored (except for updating the
* parser state by a Router-Id, Next Hop, or Update TLV,
* as described in the next section).
*/
debugf(BABEL_DEBUG_COMMON,
"Received Mandatory bit set but this FRR version is not prepared to handle it at this point");
return true;
} else if (type == SUBTLV_PADN) {
/* Nothing. */
} else if (type == SUBTLV_DIVERSITY) {
if (len > DIVERSITY_HOPS) {
flog_err(
EC_BABEL_PACKET,
"Received overlong channel information (%d > %d).n",
len, DIVERSITY_HOPS);
len = DIVERSITY_HOPS;
}
if (memchr(a + i + 2, 0, len) != NULL) {
/* 0 is reserved. */
flog_err(EC_BABEL_PACKET, "Channel information contains 0!");
return false;
}
memset(channels, 0, DIVERSITY_HOPS);
memcpy(channels, a + i + 2, len);
} else {
debugf(BABEL_DEBUG_COMMON,
"Received unknown route attribute %d.", type);
}
i += len + 2;
}
return false;
}
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[i];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 1 >= alen) {
flog_err(EC_BABEL_PACKET,
"Received truncated sub-TLV on Hello message.");
return -1;
}
len = a[i + 1];
if(i + len + 2 > alen) {
flog_err(EC_BABEL_PACKET,
"Received truncated sub-TLV on Hello message.");
return -1;
}
if (CHECK_FLAG(type, SUBTLV_MANDATORY)) {
/*
* RFC 8966 4.4
* If the mandatory bit is set, then the whole enclosing
* TLV MUST be silently ignored (except for updating the
* parser state by a Router-Id, Next Hop, or Update TLV, as
* described in the next section).
*/
debugf(BABEL_DEBUG_COMMON,
"Received subtlv with Mandatory bit, this version of FRR is not prepared to handle this currently");
return -2;
} else 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 {
flog_err(
EC_BABEL_PACKET,
"Received incorrect RTT sub-TLV on Hello message.");
}
} else {
debugf(BABEL_DEBUG_COMMON,
"Received unknown Hello sub-TLV type %d.", 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[i];
if(type == SUBTLV_PAD1) {
i++;
continue;
}
if(i + 1 >= alen) {
flog_err(EC_BABEL_PACKET,
"Received truncated sub-TLV on IHU message.");
return -1;
}
len = a[i + 1];
if(i + len + 2 > alen) {
flog_err(EC_BABEL_PACKET,
"Received truncated sub-TLV on IHU message.");
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 {
flog_err(EC_BABEL_PACKET,
"Received incorrect RTT sub-TLV on IHU message.");
}
} else {
debugf(BABEL_DEBUG_COMMON,
"Received unknown IHU sub-TLV type %d.", type);
}
i += len + 2;
}
return ret;
}
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(BABEL_DEBUG_COMMON,"Received unknown%s Route Request sub-TLV %d.",
(CHECK_FLAG(type, 0x80) != 0) ? " mandatory" : "", type);
if(CHECK_FLAG(type, 0x80) != 0)
return -1;
}
i += len + 2;
}
return 1;
fail:
flog_err(EC_BABEL_PACKET, "Received truncated sub-TLV on Route Request.");
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);
}
static int
channels_len(unsigned char *channels)
{
unsigned char *p = memchr(channels, 0, DIVERSITY_HOPS);
return p ? (p - channels) : DIVERSITY_HOPS;
}
/* Check, that the provided frame consists of a valid Babel packet header
followed by a sequence of TLVs. TLVs of known types are also checked to meet
minimum length constraints defined for each. Return 0 for no errors. */
static int
babel_packet_examin(const unsigned char *packet, int packetlen, int *blength)
{
int i = 0, bodylen;
const unsigned char *message;
unsigned char type, len;
if(packetlen < 4 || packet[0] != 42 || packet[1] != 2)
return 1;
DO_NTOHS(bodylen, packet + 2);
if(bodylen + 4 > packetlen) {
debugf(BABEL_DEBUG_COMMON, "Received truncated packet (%d + 4 > %d).",
bodylen, packetlen);
return 1;
}
while (i < bodylen){
message = packet + 4 + i;
type = message[0];
if(type == MESSAGE_PAD1) {
i++;
continue;
}
if(i + 2 > bodylen) {
debugf(BABEL_DEBUG_COMMON,"Received truncated message.");
return 1;
}
len = message[1];
if(i + len + 2 > bodylen) {
debugf(BABEL_DEBUG_COMMON,"Received truncated message.");
return 1;
}
/* not Pad1 */
if(type <= MESSAGE_MAX && tlv_min_length[type] && len < tlv_min_length[type]) {
debugf(BABEL_DEBUG_COMMON,"Undersized %u TLV", type);
return 1;
}
i += len + 2;
}
*blength = bodylen;
return 0;
}
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;
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
if (CHECK_FLAG(babel_ifp->flags, BABEL_IF_TIMESTAMPS)) {
/* We want to track exactly when we received this packet. */
gettime(&babel_now);
}
if(!linklocal(from)) {
flog_err(EC_BABEL_PACKET,
"Received packet from non-local address %s.",
format_address(from));
return;
}
if (babel_packet_examin (packet, packetlen, &bodylen)) {
flog_err(EC_BABEL_PACKET,
"Received malformed packet on %s from %s.",
ifp->name, format_address(from));
return;
}
neigh = find_neighbour(from, ifp);
if(neigh == NULL) {
flog_err(EC_BABEL_PACKET, "Couldn't allocate neighbour.");
return;
}
i = 0;
while(i < bodylen) {
message = packet + 4 + i;
type = message[0];
if(type == MESSAGE_PAD1) {
debugf(BABEL_DEBUG_COMMON,"Received pad1 from %s on %s.",
format_address(from), ifp->name);
i++;
continue;
}
len = message[1];
if(type == MESSAGE_PADN) {
debugf(BABEL_DEBUG_COMMON,"Received pad%d from %s on %s.",
len, format_address(from), ifp->name);
} else if(type == MESSAGE_ACK_REQ) {
unsigned short nonce, interval;
DO_NTOHS(nonce, message + 4);
DO_NTOHS(interval, message + 6);
debugf(BABEL_DEBUG_COMMON,"Received ack-req (%04X %d) from %s on %s.",
nonce, interval, format_address(from), ifp->name);
send_ack(neigh, nonce, interval);
} else if(type == MESSAGE_ACK) {
debugf(BABEL_DEBUG_COMMON,"Received ack from %s on %s.",
format_address(from), ifp->name);
/* Nothing right now */
} else if(type == MESSAGE_HELLO) {
unsigned short seqno, interval, flags;
int changed;
unsigned int timestamp = 0;
#define BABEL_UNICAST_HELLO 0x8000
DO_NTOHS(flags, message + 2);
/*
* RFC 8966 Appendix F
* TL;DR -> Please ignore Unicast hellos until FRR's
* BABEL is brought up to date
*/
if (CHECK_FLAG(flags, BABEL_UNICAST_HELLO)) {
debugf(BABEL_DEBUG_COMMON,
"Received Unicast Hello from %s on %s that FRR is not prepared to understand yet",
format_address(from), ifp->name);
goto done;
}
DO_NTOHS(seqno, message + 4);
DO_NTOHS(interval, message + 6);
debugf(BABEL_DEBUG_COMMON,
"Received hello %d (%d) from %s on %s.", seqno, interval,
format_address(from), ifp->name);
/*
* RFC 8966 Appendix F
* TL;DR -> Please ignore any Hello packets with the interval
* field set to 0
*/
if (interval == 0) {
debugf(BABEL_DEBUG_COMMON,
"Received hello from %s on %s should be ignored as that this version of FRR does not know how to properly handle interval == 0",
format_address(from), ifp->name);
goto done;
}
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 = babel_now;
have_hello_rtt = 1;
}
}
} else if(type == MESSAGE_IHU) {
unsigned short txcost, interval;
unsigned char address[16];
int rc;
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(BABEL_DEBUG_COMMON,"Received ihu %d (%d) from %s on %s for %s.",
txcost, interval,
format_address(from), ifp->name,
format_address(address));
if(message[2] == 0 || is_interface_ll_address(ifp, address)) {
int changed = txcost != neigh->txcost;
neigh->txcost = txcost;
neigh->ihu_time = babel_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) {
memcpy(router_id, message + 4, 8);
have_router_id = 1;
debugf(BABEL_DEBUG_COMMON,"Received router-id %s from %s on %s.",
format_eui64(router_id), format_address(from), ifp->name);
} else if(type == MESSAGE_NH) {
unsigned char nh[16];
int rc;
rc = network_address(message[2], message + 4, len - 2, nh);
if(rc <= 0) {
have_v4_nh = 0;
have_v6_nh = 0;
goto fail;
}
debugf(BABEL_DEBUG_COMMON,"Received nh %s (%d) from %s on %s.",
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;
bool ignore_update = false;
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(CHECK_FLAG(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(CHECK_FLAG(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(CHECK_FLAG(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) {
flog_err(EC_BABEL_PACKET,
"Received prefix with no router id.");
goto fail;
}
debugf(BABEL_DEBUG_COMMON,"Received update%s%s for %s from %s on %s.",
((CHECK_FLAG(message[3], 0x80)) ? "/prefix" : ""),
((CHECK_FLAG(message[3], 0x40)) ? "/id" : ""),
format_prefix(prefix, plen),
format_address(from), ifp->name);
if(message[2] == 0) {
if(metric < 0xFFFF) {
flog_err(EC_BABEL_PACKET,
"Received wildcard update with finite metric.");
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(!babel_get_if_nfo(ifp)->ipv4)
goto done;
}
if(CHECK_FLAG(babel_get_if_nfo(ifp)->flags, BABEL_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] = BABEL_IF_CHANNEL_INTERFERING;
channels[1] = 0;
}
if(parsed_len < len)
ignore_update =
parse_update_subtlv(message + 2 + parsed_len,
len - parsed_len, channels);
}
if (!ignore_update)
update_route(router_id, prefix, plen, seqno, metric,
interval, neigh, nh, channels, channels_len(channels));
} 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(BABEL_DEBUG_COMMON,"Received request with unknown AE %d. Ignoring.",
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);
debugf(BABEL_DEBUG_COMMON,"Received request for %s from %s on %s.",
message[2] == 0 ? "any" : format_prefix(prefix, plen),
format_address(from), ifp->name);
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) {
struct babel_interface *neigh_ifp =babel_get_if_nfo(neigh->ifp);
if(is_ss) {
/* Wildcard requests don't carry a source prefix. */
flog_err(EC_BABEL_PACKET,
"Received source-specific wildcard request.");
goto done;
}
/* 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 <
(time_t)(babel_now.tv_sec -
MAX(neigh_ifp->hello_interval / 100, 1)))
send_update(neigh->ifp, 0, NULL, 0);
} else {
send_update(neigh->ifp, 0, prefix, plen);
}
} else if(type == MESSAGE_MH_REQUEST) {
unsigned char prefix[16], plen;
unsigned short seqno;
int rc;
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(BABEL_DEBUG_COMMON,"Received request (%d) for %s from %s on %s (%s, %d).",
message[6],
format_prefix(prefix, plen),
format_address(from), ifp->name,
format_eui64(message + 8), seqno);
handle_request(neigh, prefix, plen, message[6], seqno, message + 8);
} else {
debugf(BABEL_DEBUG_COMMON,"Received unknown packet type %d from %s on %s.",
type, format_address(from), ifp->name);
}
done:
i += len + 2;
continue;
fail:
flog_err(EC_BABEL_PACKET,
"Couldn't parse packet (%d, %d) from %s on %s.",
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(BABEL_DEBUG_COMMON, "RTT to %s on %s sample result: %d us.",
format_address(from), ifp->name, rtt);
old_rttcost = neighbour_rttcost(neigh);
if (valid_rtt(neigh)) {
/* Running exponential average. */
smoothed_rtt = (babel_ifp->rtt_decay * rtt +
(256 - babel_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 = babel_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)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
if(babel_ifp->bucket == 0) {
int seconds = babel_now.tv_sec - babel_ifp->bucket_time;
if(seconds > 0) {
babel_ifp->bucket = MIN(BUCKET_TOKENS_MAX,
seconds * BUCKET_TOKENS_PER_SEC);
}
/* Reset bucket time unconditionally, in case clock is stepped. */
babel_ifp->bucket_time = babel_now.tv_sec;
}
if(babel_ifp->bucket > 0) {
babel_ifp->bucket--;
return 1;
} else {
return 0;
}
}
static int fill_rtt_message(struct interface *ifp)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
if(CHECK_FLAG(babel_ifp->flags, BABEL_IF_TIMESTAMPS) &&
(babel_ifp->buffered_hello >= 0)) {
if(babel_ifp->sendbuf[babel_ifp->buffered_hello + 8] == SUBTLV_PADN &&
babel_ifp->sendbuf[babel_ifp->buffered_hello + 9] == 4) {
unsigned int time;
/* Change the type of sub-TLV. */
babel_ifp->sendbuf[babel_ifp->buffered_hello + 8] =
SUBTLV_TIMESTAMP;
gettime(&babel_now);
time = time_us(babel_now);
DO_HTONL(babel_ifp->sendbuf + babel_ifp->buffered_hello + 10, time);
return 1;
} else {
flog_err(EC_BABEL_PACKET, "No space left for timestamp sub-TLV (this shouldn't happen)");
return -1;
}
}
return 0;
}
void flushbuf(struct interface *ifp)
{
int rc;
struct sockaddr_in6 sin6;
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
assert(babel_ifp->buffered <= babel_ifp->bufsize);
flushupdates(ifp);
if(babel_ifp->buffered > 0) {
debugf(BABEL_DEBUG_COMMON," (flushing %d buffered bytes on %s)",
babel_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, babel_ifp->buffered);
fill_rtt_message(ifp);
rc = babel_send(protocol_socket,
packet_header, sizeof(packet_header),
babel_ifp->sendbuf, babel_ifp->buffered,
(struct sockaddr*)&sin6, sizeof(sin6));
if(rc < 0)
flog_err(EC_BABEL_PACKET, "send: %s", safe_strerror(errno));
} else {
flog_err(EC_BABEL_PACKET, "Bucket full, dropping packet to %s.",
ifp->name);
}
}
VALGRIND_MAKE_MEM_UNDEFINED(babel_ifp->sendbuf, babel_ifp->bufsize);
babel_ifp->buffered = 0;
babel_ifp->buffered_hello = -1;
babel_ifp->have_buffered_id = 0;
babel_ifp->have_buffered_nh = 0;
babel_ifp->have_buffered_prefix = 0;
babel_ifp->flush_timeout.tv_sec = 0;
babel_ifp->flush_timeout.tv_usec = 0;
}
static void schedule_flush(struct interface *ifp)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
unsigned msecs = jitter(babel_ifp, 0);
if(babel_ifp->flush_timeout.tv_sec != 0 &&
timeval_minus_msec(&babel_ifp->flush_timeout, &babel_now) < msecs)
return;
set_timeout(&babel_ifp->flush_timeout, msecs);
}
static void schedule_flush_now(struct interface *ifp)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
/* Almost now */
unsigned msecs = roughly(10);
if(babel_ifp->flush_timeout.tv_sec != 0 &&
timeval_minus_msec(&babel_ifp->flush_timeout, &babel_now) < msecs)
return;
set_timeout(&babel_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, &babel_now) < msecs)
return;
unicast_flush_timeout.tv_usec = (babel_now.tv_usec + msecs * 1000) %1000000;
unicast_flush_timeout.tv_sec =
babel_now.tv_sec + (babel_now.tv_usec / 1000 + msecs) / 1000;
}
static void ensure_space(struct interface *ifp, int space)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
if(babel_ifp->bufsize - babel_ifp->buffered < space)
flushbuf(ifp);
}
static void start_message(struct interface *ifp, int type, int len)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
if(babel_ifp->bufsize - babel_ifp->buffered < len + 2)
flushbuf(ifp);
babel_ifp->sendbuf[babel_ifp->buffered++] = type;
babel_ifp->sendbuf[babel_ifp->buffered++] = len;
}
static void end_message(struct interface *ifp, int type, int bytes)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
assert(babel_ifp->buffered >= bytes + 2 &&
babel_ifp->sendbuf[babel_ifp->buffered - bytes - 2] == type &&
babel_ifp->sendbuf[babel_ifp->buffered - bytes - 1] == bytes);
schedule_flush(ifp);
}
static void accumulate_byte(struct interface *ifp, unsigned char value)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
babel_ifp->sendbuf[babel_ifp->buffered++] = value;
}
static void accumulate_short(struct interface *ifp, unsigned short value)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
DO_HTONS(babel_ifp->sendbuf + babel_ifp->buffered, value);
babel_ifp->buffered += 2;
}
static void accumulate_int(struct interface *ifp, unsigned int value)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
DO_HTONL(babel_ifp->sendbuf + babel_ifp->buffered, value);
babel_ifp->buffered += 4;
}
static void
accumulate_bytes(struct interface *ifp,
const unsigned char *value, unsigned len)
{
babel_interface_nfo *babel_ifp = babel_get_if_nfo(ifp);
memcpy(babel_ifp->sendbuf + babel_ifp->buffered, value, len);
babel_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, babel_get_if_nfo(neigh->ifp)->bufsize))
flush_unicast(0);
}
if(!unicast_buffer)
unicast_buffer = malloc(UNICAST_BUFSIZE);
if(!unicast_buffer) {
flog_err(EC_BABEL_MEMORY, "malloc(unicast_buffer): %s",
safe_strerror(errno));
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 &&
unicast_buffer[unicast_buffered - bytes - 2] == type &&
unicast_buffer[unicast_buffered - bytes - 1] == bytes);
schedule_unicast_flush(jitter(babel_get_if_nfo(neigh->ifp), 0));
}