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sessions.c
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/*
* Copyright (c) 2006 Sebastien Raveau <[email protected]>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. The name of the author may not be used to endorse or promote products
* derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES,
* INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
* AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
* THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
* OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
* OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
* ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*
* This file contains code for tracking TCP and VoIP (SIP & H.323) sessions.
*
* IMPORTANT: None of these features are available if libnids >= 1.21 wasn't
* found by ./configure; SIP session tracking is available only if Libosip was
* found by ./configure and H.323 session tracking is available only if
* Libooh323c was found by ./configure. These libraries can be downloaded from:
* - http://libnids.sourceforge.net/
* - https://www.gnu.org/software/osip/
* - https://sourceforge.net/projects/ooh323c/
*
* There are several entry points (from tcpslice.c) to this file:
* - sessions_init() has to be called once before any tracking can be done
* - sessions_nids_init() has to be called each time we change PCAP file
* - sessions_exit() is used to clean up and report after we're done
* - ip_callback() is called for defragmented IPv4 packets, including UDP & TCP
* - udp_callback() is called upon reception of correct UDP data
* - tcp_callback() is called upon reception of correct TCP data
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include "varattrs.h"
#include "sessions.h"
#include "diag-control.h"
/*
* The global variables below have the following purposes:
*
* `verbose' counts how many times -v was specified on the
* command line. It is currently used by sessions_add() and
* sessions_del() to show when sessions are opened and closed.
* Specify -v once and it will show opening and closing of
* primary sessions, but specify it at least twice to see
* the opening and closing of subsessions, i.e. sessions that
* are created because of some primary sessions (for example
* a SIP session will open a RTP session for the call data).
*
* `bonus_time' equals 0 when we are between the start-time and
* end-time specified by the user on the command line, and 1 when
* we are past the end-time, in which case we continue to track
* the existing sessions but ignore new sessions.
*
* `track_sessions' is a flag set by sessions_init() and
* sessions_exit() but it is mostly used in tcpslice.c to know
* whether or not to pass each PCAP frame to libnids in order to
* track sessions (it saves further processing if the user did
* not want to track sessions, which should be the case most of
* the time).
*
* `sessions_count` is the number of active sessions at a time;
* it is especially used by sessions_exit() to print a report about
* unclosed sessions in case there are any left when we are done.
*
* `sessions_file_format' is either NULL if the user does not want
* each primary session and all of its subsessions to be extracted
* and saved to separate PCAP files, or a string of the form
* "/path/filename-%s-%d.pcap", where %s will be replaced by the
* primary session type string in lowercase ("tcp", "sip" or "h323")
* and %d by the primary session ID. Note that you can specify %.6d
* instead of %d so that files can correctly be sorted by session ID
* (which will be zero-padded on the left up to six digits); this
* prevents having x-sip-10.pcap before x-sip-2.pcap for example.
*
* `sessions_expiration_delay' can be set by the user to a number
* of seconds after which an idle tracked session will be considered
* to be closed. This is useful to deal with faulty implementations
* of some protocols or packet loss, which otherwise would keep
* resources allocated until the call to sessions_exit().
*/
int verbose = 0;
int bonus_time = 0;
int track_sessions = 0;
uint32_t sessions_count = 0;
char *sessions_file_format = NULL;
time_t sessions_expiration_delay = 0;
#ifndef HAVE_LIBNIDS
void
sessions_init(const char *types _U_)
{
error("libnids required for session tracking support, sorry.");
}
void sessions_exit(void)
{
}
void sessions_nids_init(pcap_t *p _U_)
{
}
#else /* HAVE_LIBNIDS */
# include <string.h>
# include <nids.h>
# ifdef HAVE_LIBOSIPPARSER2
# include <osip2/osip.h>
# include <osipparser2/sdp_message.h>
# endif /* HAVE_LIBOSIPPARSER2 */
# ifdef HAVE_LIBOOH323C
# include <ooh323.h>
# include <ooCalls.h>
# include <printHandler.h>
# include <ooh323ep.h>
# endif /* HAVE_LIBOOH323C */
# include "tcpslice.h"
# include <netinet/ip.h>
# define IPHDRLEN (sizeof(struct ip))
# include <netinet/udp.h>
# define UDPHDRLEN (sizeof(struct udphdr))
# include <netinet/tcp.h>
# define TCPHDRLEN (sizeof(struct tcphdr))
# include <netinet/in.h>
# include <arpa/inet.h>
/*
* Session type identifiers, used as bitmasks for
* convenience in searches among tracked sessions.
*/
enum type
{
TYPE_NONE = 0x00,
TYPE_UDP = 0x01,
TYPE_TCP = 0x02,
TYPE_SIP = 0x04,
TYPE_RTP = 0x08,
TYPE_RTCP = 0x10,
TYPE_H225_RAS = 0x20,
TYPE_H225_CS = 0x40,
CLASS_SIP = TYPE_SIP | TYPE_RTP,
CLASS_H323 = TYPE_H225_RAS | TYPE_H225_CS | TYPE_RTP | TYPE_RTCP
};
/*
* Structure used by sessions and subsessions to safely share
* the same file descriptor, when they have to be saved in the
* same PCAP file and can be closed in a different order than
* they were opened.
*/
struct shared_dumper
{
char *filename;
pcap_dumper_t *filedesc;
uint32_t references;
};
/*
* (Almost) generic session description object containing
* the following properties:
* - addr: IPv4 address & port for source and destination
* - type: protocol bitmask (e.g. TYPE_UDP | TYPE_SIP)
* - id: unique number assigned to each session
* - parent_id: instead of a pointer (which is dangerous because parents
* are sometimes destroyed before their children) an ID
* that can be used to search for children of a specific session
* - parent_id: 0 for primary sessions, parent's ID for subsessions
* - timeout: when the session has to be forcefully closed
* - callback: method to call in order to process session data
* - dumper: file to which this session's packets will be extracted
* - lastseen: timestamp of the last packet in this session
* - bytes: total amount of data captured for this session
* - next: pointer to the next session in the list of all sessions
* - prev: pointer to the previous session in the list of all sessions
* - u: union containing extra properties that are needed for some session types
*/
struct session
{
struct tuple4 addr;
enum type type;
uint32_t id;
uint32_t parent_id;
time_t timeout;
struct session *(*callback)(struct session *elt, u_char *data, uint32_t len);
struct shared_dumper *dumper;
struct timeval lastseen;
uint64_t bytes;
struct session *next;
struct session *prev;
# if defined(HAVE_LIBOSIPPARSER2) || defined(HAVE_LIBOOH323C)
union
{
# ifdef HAVE_LIBOSIPPARSER2
struct
{
struct tuple4 rtp_addr;
osip_call_id_t *call_id;
int picked_up;
} sip_params;
# endif /* HAVE_LIBOSIPPARSER2 */
# ifdef HAVE_LIBOOH323C
struct
{
struct tuple4 cs_addr;
H225RequestSeqNum seqnum;
char call_id[16];
} ras_params;
# endif /* HAVE_LIBOOH323C */
} u;
# endif /* defined(HAVE_LIBOSIPPARSER2) || defined(HAVE_LIBOOH323C) */
};
/*
* Pointer to the head of the list containing all tracked sessions
*/
static struct session *first_session = NULL;
/*
* Bitmask of the session types the user asked to track
*/
static enum type sessions_track_types = TYPE_NONE;
/*
* Count how many PCAP savefiles were opened, to cope with the
* "Too many open files" errors and work around them by closing
* the oldest 10% of the file descriptors.
*/
static unsigned int dumper_fd_count = 0;
/*
* The static functions declared below have the following purposes:
*
* `sessions_add' checks if a session must be tracked or not depending on
* what the user wants (i.e. if `t' matches `sessions_track_types'); if so
* it creates a new session object, fills in the properties (based on `addr'
* and `parent' if there is one) and inserts in the list of tracked sessions.
*
* `sessions_del' properly removes a session object from the list.
*
* `sessions_find' is a small search engine acting on several criteria; it
* can search starting from the beginning of the list or from the element
* pointed by the `start' parameter, it can search for sessions with specific
* types described by the `t' parameter, or by parent ID, or most of the time
* by source and destination IP address & port.
*
* `dumper_open' and `dumper_close' manage multiple references to the same
* PCAP file used for saving packets when the user asked for extraction of
* sessions into separate files. `dumper_too_many_open_files' tries to cope
* with the "Too many open files" error that can happen when dealing with
* large PCAP files containing many simultaneous sessions.
*
* `dump_frame' actually saves the current packet to a PCAP file.
*
* `parse_type' simply converts a type from string to numerical form.
*
* `type2string' simply converts a type from numerical form to string.
*
* `ip_callback', `tcp_callback' and `udp_callback' are called from inside
* libnids upon reception of respectively IPv4, TCP and UDP packets.
*
* `sip_callback', `h225_ras_callback' and `h225_cs_callback' are called
* from `tcp_callback' and `udp_callback' via the session::callback field,
* in order to process respectively IETF's Session Initialization Protocol,
* ITU's H.225 Registration Admission Status and H.225 Call Signaling (both
* part of H.323) data.
*/
static struct session *sessions_add(const uint8_t t, const struct tuple4 *addr, const struct session *parent);
static void sessions_del(struct session *elt);
static struct session *sessions_find(struct session *start, const uint8_t t, const uint32_t parent_id, const struct tuple4 *addr);
static struct shared_dumper *dumper_open(const enum type t, const uint32_t id);
static void dumper_too_many_open_files(struct shared_dumper **d);
static void dumper_close(struct shared_dumper *d);
static void dump_frame(const u_char *data, const int len, struct shared_dumper *output);
static enum type parse_type(const char *str);
static const char *type2string(const enum type t, const int upper);
static void ip_callback(struct ip *ip, int len);
static void tcp_callback(struct tcp_stream *tcp, void **user);
static void udp_callback(struct tuple4 *addr, u_char *data, int len, struct ip *ip);
static struct session *sip_callback(struct session *elt, u_char *data, uint32_t len);
static struct session *h225_ras_callback(struct session *elt, u_char *data, uint32_t len);
static struct session *h225_cs_callback(struct session *elt, u_char *data, uint32_t len);
static enum type parse_type(const char *str)
{
if (!strcmp("tcp", str))
return TYPE_TCP;
# ifdef HAVE_LIBOSIPPARSER2
if (!strcmp("sip", str))
return CLASS_SIP;
# endif /* HAVE_LIBOSIPPARSER2 */
# ifdef HAVE_LIBOOH323C
if (!strcmp("h323", str))
return CLASS_H323;
# endif /* HAVE_LIBOOH323C */
error("unsupported session type `%s'", str);
/* NOTREACHED */
return TYPE_NONE;
}
void
sessions_init(const char *types)
{
char *comma;
bonus_time = 0;
sessions_track_types = TYPE_NONE;
while (NULL != (comma = strchr(types, ','))) {
*comma = '\0';
sessions_track_types |= parse_type(types);
types = comma + 1;
}
sessions_track_types |= parse_type(types);
while (sessions_count) {
struct session *elt = first_session;
first_session = first_session->next;
--sessions_count;
dumper_close(elt->dumper);
free(elt);
}
# ifdef HAVE_LIBOOH323C
ooH323EpInitialize(OO_CALLMODE_AUDIOCALL, "/dev/null");
ooH323EpDisableAutoAnswer();
# endif /* HAVE_LIBOOH323C */
track_sessions = 1;
}
void sessions_exit(void)
{
struct session *elt;
struct session *elt_next;
time_t one_minute_later = 0;
/*
* Last pass to close timeout'd session... It is needed
* because the last packet of a session marked for
* deletion can be followed only by non-IP packets, so
* it won't be deleted by ip_callback and would otherwise
* appear as unclosed in the report generated below.
* We jump forward one minute in order to timeout TCP
* sessions that were opened during the last minute
* of capture, which were given 60 seconds to complete
* handshake but failed to do so.
*
* Also close SIP sessions that did not result in a call:
* it happens often and the resulting spam in the report
* generated below can be really annoying.
*/
if (NULL != nids_last_pcap_header)
one_minute_later = nids_last_pcap_header->ts.tv_sec + 60;
for (elt = first_session; NULL != elt; elt = elt_next) {
elt_next = elt->next;
if (elt->timeout && (one_minute_later >= elt->timeout)) {
sessions_del(elt);
continue;
}
# ifdef HAVE_LIBOSIPPARSER2
if ((elt->type & TYPE_SIP) && !elt->u.sip_params.picked_up)
sessions_del(elt);
# endif /* HAVE_LIBOSIPPARSER2 */
}
/*
* Print a report about unclosed sessions.
*/
if (sessions_count) {
fprintf(stderr,
"%u unclosed %s (id, type, last, source, destination, bytes):\n",
sessions_count, sessions_count > 1 ? "sessions" : "session");
while (NULL != first_session) {
fprintf(stderr, "#%u\t", first_session->id);
fprintf(stderr, "%s\t", type2string(first_session->type, 1));
fprintf(stderr, "%s\t", timestamp_to_string(&first_session->lastseen));
fprintf(stderr, "%15s:%-5d\t",
inet_ntoa(*((struct in_addr *)&first_session->addr.saddr)),
first_session->addr.source);
fprintf(stderr, "%15s:%-5d\t",
inet_ntoa(*((struct in_addr *)&first_session->addr.daddr)),
first_session->addr.dest);
fprintf(stderr, "%12" PRIu64 "\n", first_session->bytes);
dumper_close(first_session->dumper);
if (NULL != first_session->next) {
first_session = first_session->next;
free(first_session->prev);
first_session->prev = NULL;
} else {
free(first_session);
first_session = NULL;
}
--sessions_count;
}
}
track_sessions = 0;
nids_exit();
}
void sessions_nids_init(pcap_t *p)
{
nids_params.pcap_desc = p;
nids_params.tcp_workarounds = 1;
if (!nids_init()) {
error("%s(): %s", __func__, nids_errbuf);
}
/*
* These conversions between function pointer and void pointer upset GCC,
* Clang and XL C.
* See also: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=83584
*/
DIAG_OFF_PEDANTIC
nids_register_ip(ip_callback);
nids_register_udp(udp_callback);
nids_register_tcp(tcp_callback);
DIAG_ON_PEDANTIC
}
static struct session *
sessions_add(const uint8_t t, const struct tuple4 *addr, const struct session *parent)
{
struct session *elt;
static uint32_t counter = 0;
if (!(t & sessions_track_types))
return NULL;
elt = calloc(1, sizeof (struct session));
elt->addr = *addr;
elt->type = t;
elt->id = ++counter;
if (sessions_expiration_delay)
elt->timeout = nids_last_pcap_header->ts.tv_sec + sessions_expiration_delay;
if (t & TYPE_SIP)
elt->callback = sip_callback;
else
if (t & TYPE_H225_RAS)
elt->callback = h225_ras_callback;
else
if (t & TYPE_H225_CS)
elt->callback = h225_cs_callback;
else
elt->callback = NULL;
if (NULL != parent) {
elt->parent_id = parent->id;
elt->dumper = parent->dumper;
elt->dumper->references++;
} else
elt->dumper = sessions_file_format ? dumper_open(t, elt->id) : NULL;
elt->next = first_session;
if (NULL != elt->next)
elt->next->prev = elt;
elt->prev = NULL;
first_session = elt;
++sessions_count;
if (verbose && (!elt->parent_id || verbose > 1))
printf("Session #%u (%s) opened at %s (active sessions total: %u)\n",
elt->parent_id ? elt->parent_id : elt->id,
type2string(t, 1),
timestamp_to_string(&nids_last_pcap_header->ts),
sessions_count);
return elt;
}
static void sessions_del(struct session *elt)
{
struct tcp_stream *tcp;
if (NULL == elt)
return;
--sessions_count;
if ((bonus_time || verbose) && (!elt->parent_id || verbose > 1))
printf("Session #%u (%s) closed at %s (active sessions total: %u)\n",
elt->parent_id ? elt->parent_id : elt->id,
type2string(elt->type, 1),
timestamp_to_string(&nids_last_pcap_header->ts),
sessions_count);
if (NULL != elt->next)
elt->next->prev = elt->prev;
if (NULL != elt->prev)
elt->prev->next = elt->next;
else
first_session = elt->next;
/*
* If this is a TCP connection, tell libnids we do not
* want to be notified of new data in this connection.
*
* We must not do it when the stream is already in a
* closing state (NIDS_CLOSE, NIDS_TIMED_OUT, NIDS_RESET
* or NIDS_EXITING) because nids_free_tcp_stream() would
* then be called twice, resulting in a crash.
*/
if ((elt->type & TYPE_TCP) &&
(NULL != (tcp = nids_find_tcp_stream(&elt->addr))) &&
(NIDS_DATA == tcp->nids_state))
nids_free_tcp_stream(tcp);
# ifdef HAVE_LIBOSIPPARSER2
/*
* If this is a SIP session, finally free the memory
* allocated for the call ID (couldn't be done before)
*/
if (elt->type & TYPE_SIP)
if (NULL != elt->u.sip_params.call_id)
osip_call_id_free(elt->u.sip_params.call_id);
# endif /* HAVE_LIBOSIPPARSER2 */
dumper_close(elt->dumper);
free(elt);
}
static struct session *
sessions_find(struct session *start, const uint8_t t, const uint32_t parent_id, const struct tuple4 *addr)
{
struct session *elt;
for (elt = start; NULL != elt; elt = elt->next) {
if (!(elt->type & t))
continue;
if (parent_id && (elt->parent_id != parent_id))
continue;
if (NULL != addr) {
if ((!elt->addr.source || elt->addr.source == addr->source) &&
(!elt->addr.dest || elt->addr.dest == addr->dest) &&
(!elt->addr.saddr || elt->addr.saddr == addr->saddr) &&
(!elt->addr.daddr || elt->addr.daddr == addr->daddr))
return elt;
if ((!elt->addr.source || elt->addr.source == addr->dest) &&
(!elt->addr.dest || elt->addr.dest == addr->source) &&
(!elt->addr.saddr || elt->addr.saddr == addr->daddr) &&
(!elt->addr.daddr || elt->addr.daddr == addr->saddr))
return elt;
}
if (parent_id)
return elt;
}
return NULL;
}
static struct shared_dumper *
dumper_open(const enum type t, const uint32_t id)
{
struct shared_dumper *d;
d = malloc(sizeof (struct shared_dumper));
d->filename = malloc(strlen(sessions_file_format) + strlen(type2string(t, 0)) + 16);
sprintf(d->filename, sessions_file_format, type2string(t, 0), id);
d->filedesc = pcap_dump_open(nids_params.pcap_desc, d->filename);
if (NULL == d->filedesc)
dumper_too_many_open_files(&d);
++dumper_fd_count;
d->references = 1;
return d;
}
static void dumper_too_many_open_files(struct shared_dumper **d)
{
struct session *elt;
unsigned int oldest_ten_percent;
oldest_ten_percent = sessions_count / 10;
if (EMFILE == errno && oldest_ten_percent) {
for (elt = first_session; NULL != elt; elt = elt->next) {
if (NULL != elt->dumper->filedesc) {
pcap_dump_close(elt->dumper->filedesc);
elt->dumper->filedesc = NULL;
--dumper_fd_count;
if (!--oldest_ten_percent)
break;
}
}
(*d)->filedesc = pcap_dump_open(nids_params.pcap_desc, (*d)->filename);
}
if (NULL == (*d)->filedesc) {
error("%s(): %s: %s", __func__,
(*d)->filename,
pcap_geterr(nids_params.pcap_desc));
}
}
static void dumper_close(struct shared_dumper *d)
{
if (NULL == d)
return;
--d->references;
if (!d->references) {
free(d->filename);
if (NULL != d->filedesc) {
pcap_dump_close(d->filedesc);
--dumper_fd_count;
}
}
}
static const char *
type2string(const enum type t, const int upper)
{
if (t & TYPE_SIP)
return upper ? "SIP" : "sip";
if ((t & TYPE_H225_RAS) || (t & TYPE_H225_CS))
return upper ? "H323" : "h323";
if (t & TYPE_RTP)
return upper ? "RTP" : "rtp";
if (t & TYPE_TCP)
return upper ? "TCP" : "tcp";
return "???";
}
static void
dump_frame(const u_char *data, const int len, struct shared_dumper *output)
{
u_char *frame;
struct pcap_pkthdr ph;
if (!bonus_time && NULL == output)
return;
frame = malloc(len + nids_linkoffset);
memcpy(frame, nids_last_pcap_data, nids_linkoffset);
memcpy(frame + nids_linkoffset, data, len);
ph.ts = nids_last_pcap_header->ts;
ph.caplen = ph.len = len + nids_linkoffset;
if (NULL != output) {
if (NULL == output->filedesc) {
output->filedesc = pcap_dump_open(nids_params.pcap_desc, output->filename);
if (NULL == output->filedesc)
dumper_too_many_open_files(&output);
++dumper_fd_count;
}
pcap_dump((u_char *)output->filedesc, &ph, frame);
}
if (bonus_time)
pcap_dump((u_char *)global_dumper, &ph, frame);
free(frame);
}
/*
* This function is called upon reception of all IPv4 packets, which
* means some packets will be processed by both ip_callback and
* {udp,tcp}_callback. It is necessary for TCP packets though because
* tcp_callback is only called once a connection is established (i.e.
* after the first SYN, SYN+ACK and ACK packets have passed) and only
* when data is available (PSH packets).
* Since we don't want failed TCP connections (portscans etc) to
* mobilize resources, we give TCP sessions 60 seconds to complete
* the TCP handshake or else they are considered to be closed.
*/
static void ip_callback(struct ip *ip, int len)
{
struct tuple4 addr;
struct tcphdr *tcp;
struct session *elt;
struct session *elt_next;
unsigned int ip_data_offset = IPHDRLEN;
if (len < 0)
error("%s(): len < 0", __func__);
for (elt = first_session; NULL != elt; elt = elt_next) {
elt_next = elt->next;
if (elt->timeout && (nids_last_pcap_header->ts.tv_sec >= elt->timeout))
sessions_del(elt);
}
if ((ip->ip_hl > 5) && ((ip->ip_hl * 4) <= len))
ip_data_offset = ip->ip_hl * 4;
if ((ip->ip_p != 6) || ((unsigned)len < (ip_data_offset + TCPHDRLEN)))
return; /* not TCP or too short */
tcp = (struct tcphdr *)((char *)ip + ip_data_offset);
addr.saddr = *((u_int *)&ip->ip_src);
addr.daddr = *((u_int *)&ip->ip_dst);
addr.source = ntohs(tcp->th_sport);
addr.dest = ntohs(tcp->th_dport);
if (NULL != (elt = sessions_find(first_session, TYPE_TCP, 0, &addr))) {
dump_frame((u_char *)ip, len, elt->dumper);
if (sessions_expiration_delay)
elt->timeout = nids_last_pcap_header->ts.tv_sec + sessions_expiration_delay;
elt->lastseen = nids_last_pcap_header->ts;
return;
}
if (!(tcp->th_flags & TH_SYN) || bonus_time)
return;
if (addr.source == 5060 || addr.dest == 5060)
elt = sessions_add(TYPE_TCP | TYPE_SIP, &addr, NULL);
else
elt = sessions_add(TYPE_TCP, &addr, NULL);
if (NULL == elt)
return;
dump_frame((u_char *)ip, len, elt->dumper);
elt->timeout = nids_last_pcap_header->ts.tv_sec + 60;
/* 60 seconds to complete TCP handshake */
}
static void udp_callback(struct tuple4 *addr, u_char *udp_data, int udp_data_len, struct ip *ip)
{
struct session *elt;
unsigned int udp_data_offset = IPHDRLEN + UDPHDRLEN;
if (NULL == (elt = sessions_find(first_session, TYPE_UDP, 0, addr))) {
if (bonus_time)
return;
if (addr->source == 1719 || addr->dest == 1719)
elt = sessions_add(TYPE_UDP | TYPE_H225_RAS, addr, NULL);
else
if (addr->source == 5060 || addr->dest == 5060)
elt = sessions_add(TYPE_UDP | TYPE_SIP, addr, NULL);
}
if (NULL == elt)
return;
elt->bytes += udp_data_len;
elt->lastseen = nids_last_pcap_header->ts;
if (NULL != elt->callback)
elt = elt->callback(elt, udp_data, udp_data_len);
/*
* We can dump the frame only after the data is processed because
* a new session object (`elt') might be created by the callback,
* with a pointer to a different PCAP file.
*/
if ((ip->ip_hl > 5) && ((ip->ip_hl * 4U) < (udp_data_offset + udp_data_len)))
udp_data_offset = ip->ip_hl * 4 + UDPHDRLEN;
dump_frame((u_char *)ip, udp_data_offset + udp_data_len, elt->dumper);
}
static void tcp_callback(struct tcp_stream *tcp, void **user)
{
struct session *elt;
struct session *rtp;
struct session *start;
switch (tcp->nids_state) {
case NIDS_JUST_EST:
if (bonus_time)
return;
elt = sessions_find(first_session, TYPE_TCP, 0, &tcp->addr);
if (NULL == elt)
return;
if (elt->type & TYPE_H225_CS) {
elt->addr.saddr = tcp->addr.saddr;
elt->addr.source = tcp->addr.source;
}
*user = elt;
if (!sessions_expiration_delay)
elt->timeout = 0;
tcp->client.collect++;
tcp->server.collect++;
return;
case NIDS_DATA:
elt = (struct session *)*user;
elt->bytes += tcp->client.count_new + tcp->server.count_new;
if (NULL != elt->callback) {
if (tcp->client.count_new)
elt->callback(elt, (u_char *)tcp->client.data, tcp->client.count_new);
if (tcp->server.count_new)
elt->callback(elt, (u_char *)tcp->server.data, tcp->server.count_new);
}
return;
case NIDS_CLOSE:
case NIDS_RESET:
case NIDS_TIMED_OUT:
elt = (struct session *)*user;
if (elt->type & TYPE_H225_CS)
for (start = first_session; NULL != (rtp = sessions_find(start, TYPE_RTP | TYPE_RTCP, elt->id, NULL)); start = rtp->next)
sessions_del(rtp);
sessions_del((struct session *)*user);
}
}
# ifndef HAVE_LIBOSIPPARSER2
static struct session *sip_callback(struct session *sip, u_char *data _U_, uint32_t len _U_)
{
return sip;
}
# else /* HAVE_LIBOSIPPARSER2 */
static int
sip_get_address(const osip_message_t *msg, u_int *host, u_short *port)
{
osip_content_type_t *ctt;
sdp_message_t *sdp;
int i;
int j;
if (NULL == (ctt = osip_message_get_content_type(msg)))
return 0;
if ((NULL == ctt->type) || (NULL == ctt->subtype))
return 0;
if (osip_strcasecmp(ctt->type, "application"))
return 0;
if (osip_strcasecmp(ctt->subtype, "sdp"))
return 0;
for (i = 0; !osip_list_eol(&msg->bodies, i); ++i) {
sdp = NULL;
sdp_message_init(&sdp);
char *tmp = ((osip_body_t *)osip_list_get(&msg->bodies, i))->body;
if (sdp_message_parse(sdp, tmp)) {
sdp_message_free(sdp);
continue;
}
for (j = 0; NULL != sdp_message_m_media_get(sdp, j); ++j) {
if (NULL == (tmp = sdp_message_m_port_get(sdp, j)))
continue;
*port = atoi(tmp);
if (NULL == (tmp = sdp_message_c_addr_get(sdp, -1, 0)))
if (NULL == (tmp = sdp_message_c_addr_get(sdp, j, 0)))
continue;
*host = (u_int)inet_addr(tmp);
sdp_message_free(sdp);
return 1;
}
sdp_message_free(sdp);
}
return 0;
}
static struct session *sip_callback(struct session *sip, u_char *data, uint32_t len)
{
osip_message_t *msg;
struct session *start;
struct session *rtp;
osip_call_id_t *call_id;
osip_message_init(&msg);
if (!osip_message_parse(msg, (char *)data, len)) {
if (NULL == sip->u.sip_params.call_id) {
/*
* If the session object was created by udp_callback
* we need to fill in the call_id field here because
* udp_callback doesn't know anything about SIP
*/
if (NULL != (call_id = osip_message_get_call_id(msg)))
osip_call_id_clone(call_id, &sip->u.sip_params.call_id);
} else {
/*
* Otherwise check if the session object passed to this
* function call was really the one corresponding to the
* call ID in the SIP packet, in case several SIP calls
* are passed upon the same transport layer protocol,
* source and destination IPv4 address & port combination.
* udp_callback has no way of knowing how to distinguish
* SIP session objects based on call ID, so we have to do
* it here. We just continue searching in the list of all
* tracked sessions for similar SIP objects until we find
* one that has the same call ID, or else we create a new
* SIP session object that corresponds to the new call.
*/
start = sip;
do {
if (NULL == (call_id = osip_message_get_call_id(msg)))
continue;
if (!osip_call_id_match(sip->u.sip_params.call_id, call_id))
break;
} while ((sip = sessions_find(sip->next, TYPE_SIP, 0, &sip->addr)));
if (NULL == sip) {
if (bonus_time) {
osip_message_free(msg);
return start;
}
sip = sessions_add(start->type, &start->addr, NULL);
if (NULL != (call_id = osip_message_get_call_id(msg)))
osip_call_id_clone(call_id, &sip->u.sip_params.call_id);
}
}
/*
* If the current SIP packet is an INVITE message, store the
* advertised source port and IPv4 address. It is not very
* important, since we can do only with the destination part
* (useful in case the capture missed the INVITE packet), but
* it helps discriminating from unrelated packets.
*
* Unfortunately, some SIP implementations such as the one in
* Audiocodes Mediant 1000 SIP gateways actually use a source
* port different from the one they advertised in the INVITE
* message parameters - how outrageous! - so we have to make
* our sessions search engine ignore the source port part by
* zeroing it :-/
*/
if (MSG_IS_INVITE(msg)) {
if (!bonus_time) {
sip_get_address(msg, &sip->u.sip_params.rtp_addr.saddr, &sip->u.sip_params.rtp_addr.source);
#ifndef USING_NON_STUPID_SIP_IMPLEMENTATIONS
sip->u.sip_params.rtp_addr.source = 0;
#endif
}
} else
if (MSG_TEST_CODE(msg, 200)) {
if (MSG_IS_RESPONSE_FOR(msg, "INVITE")) {
if (!bonus_time && sip_get_address(msg, &sip->u.sip_params.rtp_addr.daddr, &sip->u.sip_params.rtp_addr.dest)) {
sessions_add(TYPE_UDP | TYPE_RTP, &sip->u.sip_params.rtp_addr, sip);
sip->u.sip_params.picked_up = 1;
}
} else
if (MSG_IS_RESPONSE_FOR(msg, "BYE") ||
MSG_IS_RESPONSE_FOR(msg, "CANCEL")) {
start = first_session;
while (NULL != (rtp = sessions_find(start, TYPE_RTP, sip->id, NULL))) {
sessions_del(rtp);
start = rtp->next;
}
/*
* Mark for deletion in 2 seconds, in order to give some
* time to the extra ACK packets that might be exchanged
*/
if (sip->type & TYPE_UDP)
sip->timeout = nids_last_pcap_header->ts.tv_sec + 2;
}
}
}
osip_message_free(msg);
return sip;
}
# endif /* HAVE_LIBOSIPPARSER2 */
# ifndef HAVE_LIBOOH323C
static struct session *h225_ras_callback(struct session *ras, u_char *data _U_, uint32_t len _U_)
{
return ras;
}
static struct session *h225_cs_callback(struct session *cs, u_char *data _U_, uint32_t len _U_)
{
return cs;
}
# else /* HAVE_LIBOOH323C */
static struct session *h225_ras_callback(struct session *ras, u_char *data, uint32_t len)
{
OOCTXT ctxt;
H225RasMessage *pRasMsg;
struct session *cs;
struct session *rasbkp;
initContext(&ctxt);
if (ASN_OK != setPERBuffer(&ctxt, data, len, TRUE))
return ras;
rasbkp = ras;
pRasMsg = (H225RasMessage *)memAlloc(&ctxt, sizeof (H225RasMessage));
if (ASN_OK == asn1PD_H225RasMessage(&ctxt, pRasMsg))
switch (pRasMsg->t) {
case T_H225RasMessage_admissionRequest:
if (bonus_time)
break;
if ('\0' != ras->u.ras_params.call_id[0])
ras = sessions_add(TYPE_UDP | TYPE_H225_RAS, &ras->addr, NULL);
memcpy(ras->u.ras_params.call_id, pRasMsg->u.admissionRequest->conferenceID.data, 16);
ras->u.ras_params.seqnum = pRasMsg->u.admissionRequest->requestSeqNum;
ras->timeout = nids_last_pcap_header->ts.tv_sec + 60;
/* 60 seconds for the gatekeeper to confirm admission */
break;
case T_H225RasMessage_admissionConfirm:
if (bonus_time)
break;
while ((NULL != ras) && (ras->u.ras_params.seqnum != pRasMsg->u.admissionConfirm->requestSeqNum))
ras = sessions_find(ras->next, TYPE_UDP | TYPE_H225_RAS, 0, &ras->addr);
if (NULL == ras) {
ras = rasbkp;
break;
}
if (pRasMsg->u.admissionConfirm->destCallSignalAddress.t != T_H225TransportAddress_ipAddress) {
ras->timeout = nids_last_pcap_header->ts.tv_sec; /* delete after dumping frame */
break;
}
ras->u.ras_params.cs_addr.dest = pRasMsg->u.admissionConfirm->destCallSignalAddress.u.ipAddress->port;
ras->u.ras_params.cs_addr.daddr = *((u_int *)pRasMsg->u.admissionConfirm->destCallSignalAddress.u.ipAddress->ip.data);
if (NULL != (cs = sessions_add(TYPE_TCP | TYPE_H225_CS, &ras->u.ras_params.cs_addr, ras)))
cs->timeout = nids_last_pcap_header->ts.tv_sec + 60;
/* 60 seconds to establish the Call Signaling stream */
break;
case T_H225RasMessage_admissionReject:
while ((NULL != ras) && (ras->u.ras_params.seqnum != pRasMsg->u.admissionReject->requestSeqNum))
ras = sessions_find(ras->next, TYPE_UDP | TYPE_H225_RAS, 0, &ras->addr);
if (NULL == ras) {
ras = rasbkp;
break;
}
ras->timeout = nids_last_pcap_header->ts.tv_sec; /* delete after dumping frame */
break;
case T_H225RasMessage_disengageRequest:
while ((NULL != ras) && memcmp(ras->u.ras_params.call_id, pRasMsg->u.disengageRequest->conferenceID.data, 16))
ras = sessions_find(ras->next, TYPE_UDP | TYPE_H225_RAS, 0, &ras->addr);
if (NULL == ras) {
ras = rasbkp;
break;
}
ras->u.ras_params.seqnum = pRasMsg->u.disengageRequest->requestSeqNum;
break;