|
|
- --- /dev/null
- +++ b/extensions/rtsp/Kbuild
- @@ -0,0 +1,4 @@
- +# -*- Makefile -*-
- +
- +obj-m += nf_nat_rtsp.o
- +obj-m += nf_conntrack_rtsp.o
- --- /dev/null
- +++ b/extensions/rtsp/netfilter_helpers.h
- @@ -0,0 +1,133 @@
- +/*
- + * Helpers for netfiler modules. This file provides implementations for basic
- + * functions such as strncasecmp(), etc.
- + *
- + * gcc will warn for defined but unused functions, so we only include the
- + * functions requested. The following macros are used:
- + * NF_NEED_STRNCASECMP nf_strncasecmp()
- + * NF_NEED_STRTOU16 nf_strtou16()
- + * NF_NEED_STRTOU32 nf_strtou32()
- + */
- +#ifndef _NETFILTER_HELPERS_H
- +#define _NETFILTER_HELPERS_H
- +
- +/* Only include these functions for kernel code. */
- +#ifdef __KERNEL__
- +
- +#include <linux/ctype.h>
- +#define iseol(c) ( (c) == '\r' || (c) == '\n' )
- +
- +/*
- + * The standard strncasecmp()
- + */
- +#ifdef NF_NEED_STRNCASECMP
- +static int
- +nf_strncasecmp(const char* s1, const char* s2, u_int32_t len)
- +{
- + if (s1 == NULL || s2 == NULL)
- + {
- + if (s1 == NULL && s2 == NULL)
- + {
- + return 0;
- + }
- + return (s1 == NULL) ? -1 : 1;
- + }
- + while (len > 0 && tolower(*s1) == tolower(*s2))
- + {
- + len--;
- + s1++;
- + s2++;
- + }
- + return ( (len == 0) ? 0 : (tolower(*s1) - tolower(*s2)) );
- +}
- +#endif /* NF_NEED_STRNCASECMP */
- +
- +/*
- + * Parse a string containing a 16-bit unsigned integer.
- + * Returns the number of chars used, or zero if no number is found.
- + */
- +#ifdef NF_NEED_STRTOU16
- +static int
- +nf_strtou16(const char* pbuf, u_int16_t* pval)
- +{
- + int n = 0;
- +
- + *pval = 0;
- + while (isdigit(pbuf[n]))
- + {
- + *pval = (*pval * 10) + (pbuf[n] - '0');
- + n++;
- + }
- +
- + return n;
- +}
- +#endif /* NF_NEED_STRTOU16 */
- +
- +/*
- + * Parse a string containing a 32-bit unsigned integer.
- + * Returns the number of chars used, or zero if no number is found.
- + */
- +#ifdef NF_NEED_STRTOU32
- +static int
- +nf_strtou32(const char* pbuf, u_int32_t* pval)
- +{
- + int n = 0;
- +
- + *pval = 0;
- + while (pbuf[n] >= '0' && pbuf[n] <= '9')
- + {
- + *pval = (*pval * 10) + (pbuf[n] - '0');
- + n++;
- + }
- +
- + return n;
- +}
- +#endif /* NF_NEED_STRTOU32 */
- +
- +/*
- + * Given a buffer and length, advance to the next line and mark the current
- + * line.
- + */
- +#ifdef NF_NEED_NEXTLINE
- +static int
- +nf_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
- +{
- + uint off = *poff;
- + uint physlen = 0;
- +
- + if (off >= len)
- + {
- + return 0;
- + }
- +
- + while (p[off] != '\n')
- + {
- + if (len-off <= 1)
- + {
- + return 0;
- + }
- +
- + physlen++;
- + off++;
- + }
- +
- + /* if we saw a crlf, physlen needs adjusted */
- + if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
- + {
- + physlen--;
- + }
- +
- + /* advance past the newline */
- + off++;
- +
- + *plineoff = *poff;
- + *plinelen = physlen;
- + *poff = off;
- +
- + return 1;
- +}
- +#endif /* NF_NEED_NEXTLINE */
- +
- +#endif /* __KERNEL__ */
- +
- +#endif /* _NETFILTER_HELPERS_H */
- --- /dev/null
- +++ b/extensions/rtsp/netfilter_mime.h
- @@ -0,0 +1,89 @@
- +/*
- + * MIME functions for netfilter modules. This file provides implementations
- + * for basic MIME parsing. MIME headers are used in many protocols, such as
- + * HTTP, RTSP, SIP, etc.
- + *
- + * gcc will warn for defined but unused functions, so we only include the
- + * functions requested. The following macros are used:
- + * NF_NEED_MIME_NEXTLINE nf_mime_nextline()
- + */
- +#ifndef _NETFILTER_MIME_H
- +#define _NETFILTER_MIME_H
- +
- +/* Only include these functions for kernel code. */
- +#ifdef __KERNEL__
- +
- +#include <linux/ctype.h>
- +
- +/*
- + * Given a buffer and length, advance to the next line and mark the current
- + * line. If the current line is empty, *plinelen will be set to zero. If
- + * not, it will be set to the actual line length (including CRLF).
- + *
- + * 'line' in this context means logical line (includes LWS continuations).
- + * Returns 1 on success, 0 on failure.
- + */
- +#ifdef NF_NEED_MIME_NEXTLINE
- +static int
- +nf_mime_nextline(char* p, uint len, uint* poff, uint* plineoff, uint* plinelen)
- +{
- + uint off = *poff;
- + uint physlen = 0;
- + int is_first_line = 1;
- +
- + if (off >= len)
- + {
- + return 0;
- + }
- +
- + do
- + {
- + while (p[off] != '\n')
- + {
- + if (len-off <= 1)
- + {
- + return 0;
- + }
- +
- + physlen++;
- + off++;
- + }
- +
- + /* if we saw a crlf, physlen needs adjusted */
- + if (physlen > 0 && p[off] == '\n' && p[off-1] == '\r')
- + {
- + physlen--;
- + }
- +
- + /* advance past the newline */
- + off++;
- +
- + /* check for an empty line */
- + if (physlen == 0)
- + {
- + break;
- + }
- +
- + /* check for colon on the first physical line */
- + if (is_first_line)
- + {
- + is_first_line = 0;
- + if (memchr(p+(*poff), ':', physlen) == NULL)
- + {
- + return 0;
- + }
- + }
- + }
- + while (p[off] == ' ' || p[off] == '\t');
- +
- + *plineoff = *poff;
- + *plinelen = (physlen == 0) ? 0 : (off - *poff);
- + *poff = off;
- +
- + return 1;
- +}
- +#endif /* NF_NEED_MIME_NEXTLINE */
- +
- +#endif /* __KERNEL__ */
- +
- +#endif /* _NETFILTER_MIME_H */
- --- /dev/null
- +++ b/extensions/rtsp/nf_conntrack_rtsp.c
- @@ -0,0 +1,732 @@
- +/*
- + * RTSP extension for IP connection tracking
- + * (C) 2003 by Tom Marshall <tmarshall at real.com>
- + *
- + * 2005-02-13: Harald Welte <laforge at netfilter.org>
- + * - port to 2.6
- + * - update to recent post-2.6.11 api changes
- + * 2006-09-14: Steven Van Acker <deepstar at singularity.be>
- + * - removed calls to NAT code from conntrack helper: NAT no longer needed to use rtsp-conntrack
- + * 2007-04-18: Michael Guntsche <mike at it-loops.com>
- + * - Port to new NF API
- + * 2013-03-04: Il'inykh Sergey <sergeyi at inango-sw.com>. Inango Systems Ltd
- + * - fixed rtcp nat mapping and other port mapping fixes
- + * - simple TEARDOWN request handling
- + * - codestyle fixes and other less significant bug fixes
- + * 2018-04-17: Alin Nastac <alin.nastac at gmail.com>
- + * Hans Dedecker <dedeckeh at gmail.com>
- + * - use IP address read from SETUP URI in expected connections
- + * 2018-04-18: Hans Dedecker <dedeckeh at gmail.com>
- + * - update RTP expected connection source IP based on SOURCE
- + * in the SETUP reply message
- + *
- + * based on ip_conntrack_irc.c
- + *
- + * This program is free software; you can redistribute it and/or
- + * modify it under the terms of the GNU General Public License
- + * as published by the Free Software Foundation; either version
- + * 2 of the License, or (at your option) any later version.
- + *
- + * Module load syntax:
- + * insmod nf_conntrack_rtsp.o ports=port1,port2,...port<MAX_PORTS>
- + * max_outstanding=n setup_timeout=secs
- + *
- + * If no ports are specified, the default will be port 554.
- + *
- + * With max_outstanding you can define the maximum number of not yet
- + * answered SETUP requests per RTSP session (default 8).
- + * With setup_timeout you can specify how long the system waits for
- + * an expected data channel (default 300 seconds).
- + *
- + */
- +
- +#include <linux/module.h>
- +#include <linux/netfilter.h>
- +#include <linux/ip.h>
- +#include <linux/inet.h>
- +#include <net/tcp.h>
- +
- +#include <net/netfilter/nf_conntrack.h>
- +#include <net/netfilter/nf_conntrack_expect.h>
- +#include <net/netfilter/nf_conntrack_helper.h>
- +#include "nf_conntrack_rtsp.h"
- +
- +#define NF_NEED_STRNCASECMP
- +#define NF_NEED_STRTOU16
- +#define NF_NEED_STRTOU32
- +#define NF_NEED_NEXTLINE
- +#include "netfilter_helpers.h"
- +#define NF_NEED_MIME_NEXTLINE
- +#include "netfilter_mime.h"
- +
- +#include <linux/ctype.h>
- +
- +#define MAX_PORTS 8
- +static int ports[MAX_PORTS];
- +static int num_ports = 0;
- +static int max_outstanding = 8;
- +static unsigned int setup_timeout = 300;
- +
- +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
- +MODULE_DESCRIPTION("RTSP connection tracking module");
- +MODULE_LICENSE("GPL");
- +module_param_array(ports, int, &num_ports, 0400);
- +MODULE_PARM_DESC(ports, "port numbers of RTSP servers");
- +module_param(max_outstanding, int, 0400);
- +MODULE_PARM_DESC(max_outstanding, "max number of outstanding SETUP requests per RTSP session");
- +module_param(setup_timeout, int, 0400);
- +MODULE_PARM_DESC(setup_timeout, "timeout on for unestablished data channels");
- +
- +static char *rtsp_buffer;
- +static DEFINE_SPINLOCK(rtsp_buffer_lock);
- +
- +static struct nf_conntrack_expect_policy rtsp_exp_policy;
- +
- +unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
- + enum ip_conntrack_info ctinfo,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + unsigned int protoff,
- +#endif
- + unsigned int matchoff, unsigned int matchlen,
- + struct ip_ct_rtsp_expect* prtspexp,
- + struct nf_conntrack_expect *rtp_exp,
- + struct nf_conntrack_expect *rtcp_exp);
- +
- +EXPORT_SYMBOL_GPL(nf_nat_rtsp_hook);
- +
- +/*
- + * Max mappings we will allow for one RTSP connection (for RTP, the number
- + * of allocated ports is twice this value). Note that SMIL burns a lot of
- + * ports so keep this reasonably high. If this is too low, you will see a
- + * lot of "no free client map entries" messages.
- + */
- +#define MAX_PORT_MAPS 16
- +
- +/*** default port list was here in the masq code: 554, 3030, 4040 ***/
- +
- +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
- +
- +/*
- + * Parse an RTSP packet.
- + *
- + * Returns zero if parsing failed.
- + *
- + * Parameters:
- + * IN ptcp tcp data pointer
- + * IN tcplen tcp data len
- + * IN/OUT ptcpoff points to current tcp offset
- + * OUT phdrsoff set to offset of rtsp headers
- + * OUT phdrslen set to length of rtsp headers
- + * OUT pcseqoff set to offset of CSeq header
- + * OUT pcseqlen set to length of CSeq header
- + */
- +static int
- +rtsp_parse_message(char* ptcp, uint tcplen, uint* ptcpoff,
- + uint* phdrsoff, uint* phdrslen,
- + uint* pcseqoff, uint* pcseqlen,
- + uint* transoff, uint* translen)
- +{
- + uint entitylen = 0;
- + uint lineoff;
- + uint linelen;
- +
- + if (!nf_nextline(ptcp, tcplen, ptcpoff, &lineoff, &linelen))
- + return 0;
- +
- + *phdrsoff = *ptcpoff;
- + while (nf_mime_nextline(ptcp, tcplen, ptcpoff, &lineoff, &linelen)) {
- + if (linelen == 0) {
- + if (entitylen > 0)
- + *ptcpoff += min(entitylen, tcplen - *ptcpoff);
- + break;
- + }
- + if (lineoff+linelen > tcplen) {
- + pr_info("!! overrun !!\n");
- + break;
- + }
- +
- + if (nf_strncasecmp(ptcp+lineoff, "CSeq:", 5) == 0) {
- + *pcseqoff = lineoff;
- + *pcseqlen = linelen;
- + }
- +
- + if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0) {
- + *transoff = lineoff;
- + *translen = linelen;
- + }
- +
- + if (nf_strncasecmp(ptcp+lineoff, "Content-Length:", 15) == 0) {
- + uint off = lineoff+15;
- + SKIP_WSPACE(ptcp+lineoff, linelen, off);
- + nf_strtou32(ptcp+off, &entitylen);
- + }
- + }
- + *phdrslen = (*ptcpoff) - (*phdrsoff);
- +
- + return 1;
- +}
- +
- +/*
- + * Find lo/hi client ports and/or source (if any) in transport header
- + * In:
- + * ptcp, tcplen = packet
- + * tranoff, tranlen = buffer to search
- + *
- + * Out:
- + * pport_lo, pport_hi = lo/hi ports (host endian)
- + * srvaddr
- + *
- + * Returns nonzero if any client ports found
- + *
- + * Note: it is valid (and expected) for the client to request multiple
- + * transports, so we need to parse the entire line.
- + */
- +static int
- +rtsp_parse_transport(char* ptran, uint tranlen,
- + struct ip_ct_rtsp_expect* prtspexp)
- +{
- + int rc = 0;
- + uint off = 0;
- +
- + if (tranlen < 10 || !iseol(ptran[tranlen-1]) ||
- + nf_strncasecmp(ptran, "Transport:", 10) != 0) {
- + pr_info("sanity check failed\n");
- + return 0;
- + }
- +
- + pr_debug("tran='%.*s'\n", (int)tranlen, ptran);
- + off += 10;
- + SKIP_WSPACE(ptran, tranlen, off);
- +
- + /* Transport: tran;field;field=val,tran;field;field=val,... */
- + while (off < tranlen) {
- + const char* pparamend;
- + uint nextparamoff;
- +
- + pparamend = memchr(ptran+off, ',', tranlen-off);
- + pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
- + nextparamoff = pparamend-ptran;
- +
- + while (off < nextparamoff) {
- + const char* pfieldend;
- + uint nextfieldoff;
- +
- + pfieldend = memchr(ptran+off, ';', nextparamoff-off);
- + nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
- +
- + if (strncmp(ptran+off, "client_port=", 12) == 0) {
- + u_int16_t port;
- + uint numlen;
- +
- + off += 12;
- + numlen = nf_strtou16(ptran+off, &port);
- + off += numlen;
- + if (prtspexp->loport != 0 && prtspexp->loport != port)
- + pr_debug("multiple ports found, port %hu ignored\n", port);
- + else {
- + pr_debug("lo port found : %hu\n", port);
- + prtspexp->loport = prtspexp->hiport = port;
- + if (ptran[off] == '-') {
- + off++;
- + numlen = nf_strtou16(ptran+off, &port);
- + off += numlen;
- + prtspexp->pbtype = pb_range;
- + prtspexp->hiport = port;
- +
- + // If we have a range, assume rtp:
- + // loport must be even, hiport must be loport+1
- + if ((prtspexp->loport & 0x0001) != 0 ||
- + prtspexp->hiport != prtspexp->loport+1) {
- + pr_debug("incorrect range: %hu-%hu, correcting\n",
- + prtspexp->loport, prtspexp->hiport);
- + prtspexp->loport &= 0xfffe;
- + prtspexp->hiport = prtspexp->loport+1;
- + }
- + } else if (ptran[off] == '/') {
- + off++;
- + numlen = nf_strtou16(ptran+off, &port);
- + off += numlen;
- + prtspexp->pbtype = pb_discon;
- + prtspexp->hiport = port;
- + }
- + rc = 1;
- + }
- + } else if (strncmp(ptran+off, "source=", 7) == 0) {
- + uint srcaddrlen;
- +
- + off += 7;
- + srcaddrlen = nextfieldoff - off - 1;
- +
- + if (in4_pton(ptran + off, srcaddrlen,
- + (u8 *)&prtspexp->srvaddr.in,
- + -1, NULL))
- + pr_debug("source found : %pI4\n",
- + &prtspexp->srvaddr.ip);
- + }
- +
- + /*
- + * Note we don't look for the destination parameter here.
- + * If we are using NAT, the NAT module will handle it. If not,
- + * and the client is sending packets elsewhere, the expectation
- + * will quietly time out.
- + */
- +
- + off = nextfieldoff;
- + }
- +
- + off = nextparamoff;
- + }
- +
- + return rc;
- +}
- +
- +
- +/*** conntrack functions ***/
- +
- +/* outbound packet: client->server */
- +
- +static inline int
- +help_out(struct sk_buff *skb, unsigned char *rb_ptr, unsigned int datalen,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + struct nf_conn *ct, enum ip_conntrack_info ctinfo,
- + unsigned int protoff)
- +#else
- + struct nf_conn *ct, enum ip_conntrack_info ctinfo)
- +#endif
- +{
- + struct ip_ct_rtsp_expect expinfo;
- +
- + int dir = CTINFO2DIR(ctinfo); /* = IP_CT_DIR_ORIGINAL */
- + //struct tcphdr* tcph = (void*)iph + iph->ihl * 4;
- + //uint tcplen = pktlen - iph->ihl * 4;
- + char* pdata = rb_ptr;
- + //uint datalen = tcplen - tcph->doff * 4;
- + uint dataoff = 0;
- + int ret = NF_ACCEPT;
- +
- + struct nf_conntrack_expect *rtp_exp;
- + struct nf_conntrack_expect *rtcp_exp = NULL;
- +
- + __be16 be_loport;
- + __be16 be_hiport;
- +
- + typeof(nf_nat_rtsp_hook) nf_nat_rtsp;
- +
- + memset(&expinfo, 0, sizeof(expinfo));
- +
- + while (dataoff < datalen) {
- + uint cmdoff = dataoff;
- + uint hdrsoff = 0;
- + uint hdrslen = 0;
- + uint cseqoff = 0;
- + uint cseqlen = 0;
- + uint transoff = 0;
- + uint translen = 0;
- + uint off;
- + union nf_inet_addr srvaddr;
- +
- + if (!rtsp_parse_message(pdata, datalen, &dataoff,
- + &hdrsoff, &hdrslen,
- + &cseqoff, &cseqlen,
- + &transoff, &translen))
- + break; /* not a valid message */
- +
- + if (strncmp(pdata+cmdoff, "TEARDOWN ", 9) == 0) {
- + pr_debug("teardown handled\n");
- + nf_ct_remove_expectations(ct); /* FIXME must be session id aware */
- + break;
- + }
- +
- + if (strncmp(pdata+cmdoff, "SETUP ", 6) != 0)
- + continue; /* not a SETUP message */
- +
- + srvaddr = ct->tuplehash[!dir].tuple.src.u3;
- +
- + /* try to get RTP media source from SETUP URI */
- + off = cmdoff + 6;
- + while (off < datalen) {
- + if (strncmp(pdata+off, "://", 3) == 0) {
- + off += 3;
- + cmdoff = off;
- +
- + while (off < datalen) {
- + if (pdata[off] == ':' ||
- + pdata[off] == '/' ||
- + pdata[off] == ' ') {
- + in4_pton(pdata + cmdoff,
- + off - cmdoff,
- + (u8 *)&srvaddr.in,
- + -1, NULL);
- + break;
- + }
- + off++;
- + }
- + break;
- + }
- + off++;
- + }
- +
- + pr_debug("found a setup message\n");
- +
- + off = 0;
- + if(translen)
- + rtsp_parse_transport(pdata+transoff, translen, &expinfo);
- +
- + if (expinfo.loport == 0) {
- + pr_debug("no udp transports found\n");
- + continue; /* no udp transports found */
- + }
- +
- + pr_debug("udp transport found, ports=(%d,%hu,%hu)\n",
- + (int)expinfo.pbtype, expinfo.loport, expinfo.hiport);
- +
- +
- + be_loport = htons(expinfo.loport);
- +
- + rtp_exp = nf_ct_expect_alloc(ct);
- + if (rtp_exp == NULL) {
- + ret = NF_DROP;
- + goto out;
- + }
- +
- + nf_ct_expect_init(rtp_exp, NF_CT_EXPECT_CLASS_DEFAULT,
- + nf_ct_l3num(ct), &srvaddr,
- + &ct->tuplehash[!dir].tuple.dst.u3,
- + IPPROTO_UDP, NULL, &be_loport);
- +
- + rtp_exp->flags = 0;
- +
- + if (expinfo.pbtype == pb_range) {
- + pr_debug("setup expectation for rtcp\n");
- +
- + be_hiport = htons(expinfo.hiport);
- + rtcp_exp = nf_ct_expect_alloc(ct);
- + if (rtcp_exp == NULL) {
- + ret = NF_DROP;
- + goto out1;
- + }
- +
- + nf_ct_expect_init(rtcp_exp, NF_CT_EXPECT_CLASS_DEFAULT,
- + nf_ct_l3num(ct), &srvaddr,
- + &ct->tuplehash[!dir].tuple.dst.u3,
- + IPPROTO_UDP, NULL, &be_hiport);
- +
- + rtcp_exp->flags = 0;
- +
- + pr_debug("expect_related %pI4:%u-%u-%pI4:%u-%u\n",
- + &rtp_exp->tuple.src.u3.ip,
- + ntohs(rtp_exp->tuple.src.u.udp.port),
- + ntohs(rtcp_exp->tuple.src.u.udp.port),
- + &rtp_exp->tuple.dst.u3.ip,
- + ntohs(rtp_exp->tuple.dst.u.udp.port),
- + ntohs(rtcp_exp->tuple.dst.u.udp.port));
- + } else {
- + pr_debug("expect_related %pI4:%u-%pI4:%u\n",
- + &rtp_exp->tuple.src.u3.ip,
- + ntohs(rtp_exp->tuple.src.u.udp.port),
- + &rtp_exp->tuple.dst.u3.ip,
- + ntohs(rtp_exp->tuple.dst.u.udp.port));
- + }
- +
- + nf_nat_rtsp = rcu_dereference(nf_nat_rtsp_hook);
- + if (nf_nat_rtsp && ct->status & IPS_NAT_MASK)
- + /* pass the request off to the nat helper */
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + ret = nf_nat_rtsp(skb, ctinfo, protoff, hdrsoff, hdrslen,
- + &expinfo, rtp_exp, rtcp_exp);
- +#else
- + ret = nf_nat_rtsp(skb, ctinfo, hdrsoff, hdrslen,
- + &expinfo, rtp_exp, rtcp_exp);
- +#endif
- + else {
- + if (nf_ct_expect_related(rtp_exp) == 0) {
- + if (rtcp_exp && nf_ct_expect_related(rtcp_exp) != 0) {
- + nf_ct_unexpect_related(rtp_exp);
- + pr_info("nf_conntrack_expect_related failed for rtcp\n");
- + ret = NF_DROP;
- + }
- + } else {
- + pr_info("nf_conntrack_expect_related failed for rtp\n");
- + ret = NF_DROP;
- + }
- + }
- + if (rtcp_exp) {
- + nf_ct_expect_put(rtcp_exp);
- + }
- +out1:
- + nf_ct_expect_put(rtp_exp);
- + goto out;
- + }
- +out:
- +
- + return ret;
- +}
- +
- +
- +static inline int
- +help_in(struct sk_buff *skb, unsigned char *rb_ptr, unsigned int datalen,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + struct nf_conn *ct, enum ip_conntrack_info ctinfo,
- + unsigned int protoff)
- +#else
- + struct nf_conn *ct, enum ip_conntrack_info ctinfo)
- +#endif
- + {
- + struct ip_ct_rtsp_expect expinfo;
- + union nf_inet_addr srvaddr;
- + int dir = CTINFO2DIR(ctinfo); /* = IP_CT_DIR_ORIGINAL */
- + int len;
- + char* pdata = rb_ptr;
- + uint dataoff = 0;
- + int ret = NF_ACCEPT;
- + u_int8_t family;
- + struct nf_conntrack_expect *exp_ct = NULL;
- + struct nf_conntrack_tuple t;
- + struct net *net = nf_ct_net(ct);
- +
- + memset(&expinfo, 0, sizeof(expinfo));
- +
- + while (dataoff < datalen) {
- + uint cmdoff = dataoff;
- + uint hdrsoff = 0;
- + uint hdrslen = 0;
- + uint cseqoff = 0;
- + uint cseqlen = 0;
- + uint transoff = 0;
- + uint translen = 0;
- +
- + if (!rtsp_parse_message(pdata, datalen, &dataoff,
- + &hdrsoff, &hdrslen,
- + &cseqoff, &cseqlen,
- + &transoff, &translen))
- + break; /* not a valid message */
- +
- + if (strncmp(pdata+cmdoff, "RTSP/", 5) == 0 && translen) {
- + union nf_inet_addr zeroaddr;
- +
- + memset(&zeroaddr, 0, sizeof(zeroaddr));
- +
- + if (!rtsp_parse_transport(pdata+transoff, translen, &expinfo))
- + continue;
- +
- + srvaddr = expinfo.srvaddr;
- +
- + if (nf_inet_addr_cmp(&srvaddr, &ct->tuplehash[dir].tuple.src.u3) ||
- + nf_inet_addr_cmp(&srvaddr, &zeroaddr))
- + continue;
- + } else
- + continue; /* not valid RTSP reply */
- +
- + if (expinfo.loport == 0) {
- + pr_debug("no udp transports found\n");
- + continue; /* no udp transports found */
- + }
- +
- + family = nf_ct_l3num(ct);
- + if (family == AF_INET)
- + len = 4;
- + else
- + len = 16;
- +
- + /* replace rtp expect src addr */
- + t.src.l3num = family;
- + t.dst.protonum = IPPROTO_UDP;
- +
- + memcpy(&t.src.u3, &ct->tuplehash[dir].tuple.src.u3, len);
- + if (sizeof(t.src.u3) > len)
- + /* address needs to be cleared for nf_ct_tuple_equal */
- + memset((void *)&t.src.u3 + len, 0, sizeof(t.src.u3) - len);
- +
- + t.src.u.all = 0;
- +
- + memcpy(&t.dst.u3, &ct->tuplehash[dir].tuple.dst.u3, len);
- + if (sizeof(t.dst.u3) > len)
- + /* address needs to be cleared for nf_ct_tuple_equal */
- + memset((void *)&t.dst.u3 + len, 0, sizeof(t.dst.u3) - len);
- +
- + t.dst.u.all = htons(expinfo.loport);
- +
- + /* get the rtp expect and replace the srcaddr with RTP server addr */
- + exp_ct = nf_ct_expect_find_get(net, nf_ct_zone(ct), &t);
- + if (exp_ct) {
- + memcpy(&exp_ct->tuple.src.u3, &srvaddr, len);
- + if (sizeof(exp_ct->tuple.src.u3) > len)
- + /* address needs to be cleared for nf_ct_tuple_equal */
- + memset((void *)&exp_ct->tuple.src.u3 + len, 0,
- + sizeof(exp_ct->tuple.src.u3) - len);
- + } else
- + goto out;
- +
- + /* replace rtcp expect src addr */
- + if (expinfo.pbtype == pb_range) {
- + t.dst.u.all = htons(expinfo.hiport);
- +
- + /* get the rtcp expect and replace the srcaddr with RTP server addr */
- + exp_ct = nf_ct_expect_find_get(net, nf_ct_zone(ct), &t);
- + if (exp_ct) {
- + memcpy(&exp_ct->tuple.src.u3, &srvaddr, len);
- + if (sizeof(exp_ct->tuple.src.u3) > len)
- + /* address needs to be cleared for nf_ct_tuple_equal */
- + memset((void *)&exp_ct->tuple.src.u3 + len, 0,
- + sizeof(exp_ct->tuple.src.u3) - len);
- + } else
- + goto out;
- + }
- +
- + goto out;
- + }
- +out:
- + return ret;
- + }
- +
- +static int help(struct sk_buff *skb, unsigned int protoff,
- + struct nf_conn *ct, enum ip_conntrack_info ctinfo)
- +{
- + struct tcphdr _tcph, *th;
- + unsigned int dataoff, datalen;
- + char *rb_ptr;
- + int ret = NF_DROP;
- +
- + /* Until there's been traffic both ways, don't look in packets. */
- + if (ctinfo != IP_CT_ESTABLISHED &&
- + ctinfo != IP_CT_ESTABLISHED + IP_CT_IS_REPLY) {
- + pr_debug("conntrackinfo = %u\n", ctinfo);
- + return NF_ACCEPT;
- + }
- +
- + /* Not whole TCP header? */
- + th = skb_header_pointer(skb, protoff, sizeof(_tcph), &_tcph);
- +
- + if (!th)
- + return NF_ACCEPT;
- +
- + /* No data ? */
- + dataoff = protoff + th->doff*4;
- + datalen = skb->len - dataoff;
- + if (dataoff >= skb->len)
- + return NF_ACCEPT;
- +
- + spin_lock_bh(&rtsp_buffer_lock);
- + rb_ptr = skb_header_pointer(skb, dataoff,
- + skb->len - dataoff, rtsp_buffer);
- + BUG_ON(rb_ptr == NULL);
- +
- +#if 0
- + /* Checksum invalid? Ignore. */
- + /* FIXME: Source route IP option packets --RR */
- + if (tcp_v4_check(tcph, tcplen, iph->saddr, iph->daddr,
- + csum_partial((char*)tcph, tcplen, 0)))
- + {
- + DEBUGP("bad csum: %p %u %u.%u.%u.%u %u.%u.%u.%u\n",
- + tcph, tcplen, NIPQUAD(iph->saddr), NIPQUAD(iph->daddr));
- + return NF_ACCEPT;
- + }
- +#endif
- +
- + switch (CTINFO2DIR(ctinfo)) {
- + case IP_CT_DIR_ORIGINAL:
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + ret = help_out(skb, rb_ptr, datalen, ct, ctinfo, protoff);
- +#else
- + ret = help_out(skb, rb_ptr, datalen, ct, ctinfo);
- +#endif
- + break;
- + case IP_CT_DIR_REPLY:
- + pr_debug("IP_CT_DIR_REPLY\n");
- + /* inbound packet: server->client */
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + ret = help_in(skb, rb_ptr, datalen, ct, ctinfo, protoff);
- +#else
- + ret = help_in(skb, rb_ptr, datalen, ct, ctinfo);
- +#endif
- + break;
- + }
- +
- + spin_unlock_bh(&rtsp_buffer_lock);
- +
- + return ret;
- +}
- +
- +static struct nf_conntrack_helper rtsp_helpers[MAX_PORTS];
- +static char rtsp_names[MAX_PORTS][10];
- +
- +/* This function is intentionally _NOT_ defined as __exit */
- +static void
- +fini(void)
- +{
- + int i;
- + for (i = 0; i < num_ports; i++) {
- + pr_debug("unregistering port %d\n", ports[i]);
- + nf_conntrack_helper_unregister(&rtsp_helpers[i]);
- + }
- + kfree(rtsp_buffer);
- +}
- +
- +static int __init
- +init(void)
- +{
- + int i, ret;
- + struct nf_conntrack_helper *hlpr;
- + char *tmpname;
- +
- + printk("nf_conntrack_rtsp v" IP_NF_RTSP_VERSION " loading\n");
- +
- + if (max_outstanding < 1) {
- + printk("nf_conntrack_rtsp: max_outstanding must be a positive integer\n");
- + return -EBUSY;
- + }
- + if (setup_timeout < 0) {
- + printk("nf_conntrack_rtsp: setup_timeout must be a positive integer\n");
- + return -EBUSY;
- + }
- +
- + rtsp_exp_policy.max_expected = max_outstanding;
- + rtsp_exp_policy.timeout = setup_timeout;
- +
- + rtsp_buffer = kmalloc(65536, GFP_KERNEL);
- + if (!rtsp_buffer)
- + return -ENOMEM;
- +
- + /* If no port given, default to standard rtsp port */
- + if (ports[0] == 0) {
- + ports[0] = RTSP_PORT;
- + num_ports = 1;
- + }
- +
- + for (i = 0; (i < MAX_PORTS) && ports[i]; i++) {
- + hlpr = &rtsp_helpers[i];
- + memset(hlpr, 0, sizeof(struct nf_conntrack_helper));
- + hlpr->tuple.src.l3num = AF_INET;
- + hlpr->tuple.src.u.tcp.port = htons(ports[i]);
- + hlpr->tuple.dst.protonum = IPPROTO_TCP;
- + hlpr->expect_policy = &rtsp_exp_policy;
- + hlpr->me = THIS_MODULE;
- + hlpr->help = help;
- +
- + tmpname = &rtsp_names[i][0];
- + if (ports[i] == RTSP_PORT) {
- + sprintf(tmpname, "rtsp");
- + } else {
- + sprintf(tmpname, "rtsp-%d", i);
- + }
- +
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,6,0)
- + strlcpy(hlpr->name, tmpname, sizeof(hlpr->name));
- +#else
- + hlpr->name = tmpname;
- +#endif
- + pr_debug("port #%d: %d\n", i, ports[i]);
- +
- + ret = nf_conntrack_helper_register(hlpr);
- +
- + if (ret) {
- + printk("nf_conntrack_rtsp: ERROR registering port %d\n", ports[i]);
- + fini();
- + return -EBUSY;
- + }
- + }
- + return 0;
- +}
- +
- +module_init(init);
- +module_exit(fini);
- --- /dev/null
- +++ b/extensions/rtsp/nf_conntrack_rtsp.h
- @@ -0,0 +1,73 @@
- +/*
- + * RTSP extension for IP connection tracking.
- + * (C) 2003 by Tom Marshall <tmarshall at real.com>
- + * based on ip_conntrack_irc.h
- + *
- + * This program is free software; you can redistribute it and/or
- + * modify it under the terms of the GNU General Public License
- + * as published by the Free Software Foundation; either version
- + * 2 of the License, or (at your option) any later version.
- + *
- + * 2013-03-04: Il'inykh Sergey <sergeyi at inango-sw.com>. Inango Systems Ltd
- + * - conditional compilation for kernel 3.7
- + * - port mapping improvements
- +*/
- +#ifndef _IP_CONNTRACK_RTSP_H
- +#define _IP_CONNTRACK_RTSP_H
- +
- +#include <linux/version.h>
- +
- +//#define IP_NF_RTSP_DEBUG 1
- +#define IP_NF_RTSP_VERSION "0.7"
- +
- +#ifdef __KERNEL__
- +/* port block types */
- +typedef enum {
- + pb_single, /* client_port=x */
- + pb_range, /* client_port=x-y */
- + pb_discon /* client_port=x/y (rtspbis) */
- +} portblock_t;
- +
- +/* We record seq number and length of rtsp headers here, all in host order. */
- +
- +/*
- + * This structure is per expected connection. It is a member of struct
- + * ip_conntrack_expect. The TCP SEQ for the conntrack expect is stored
- + * there and we are expected to only store the length of the data which
- + * needs replaced. If a packet contains multiple RTSP messages, we create
- + * one expected connection per message.
- + *
- + * We use these variables to mark the entire header block. This may seem
- + * like overkill, but the nature of RTSP requires it. A header may appear
- + * multiple times in a message. We must treat two Transport headers the
- + * same as one Transport header with two entries.
- + */
- +struct ip_ct_rtsp_expect
- +{
- + u_int32_t len; /* length of header block */
- + portblock_t pbtype; /* Type of port block that was requested */
- + u_int16_t loport; /* Port that was requested, low or first */
- + u_int16_t hiport; /* Port that was requested, high or second */
- + union nf_inet_addr srvaddr; /* src address in SETUP reply */
- +#if 0
- + uint method; /* RTSP method */
- + uint cseq; /* CSeq from request */
- +#endif
- +};
- +
- +extern unsigned int (*nf_nat_rtsp_hook)(struct sk_buff *skb,
- + enum ip_conntrack_info ctinfo,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + unsigned int protoff,
- +#endif
- + unsigned int matchoff,
- + unsigned int matchlen,
- + struct ip_ct_rtsp_expect *prtspexp,
- + struct nf_conntrack_expect *rtp_exp,
- + struct nf_conntrack_expect *rtcp_exp);
- +
- +#define RTSP_PORT 554
- +
- +#endif /* __KERNEL__ */
- +
- +#endif /* _IP_CONNTRACK_RTSP_H */
- --- /dev/null
- +++ b/extensions/rtsp/nf_nat_rtsp.c
- @@ -0,0 +1,617 @@
- +/*
- + * RTSP extension for TCP NAT alteration
- + * (C) 2003 by Tom Marshall <tmarshall at real.com>
- + *
- + * 2013-03-04: Il'inykh Sergey <sergeyi at inango-sw.com>. Inango Systems Ltd
- + * - fixed rtcp nat mapping and other port mapping fixes
- + * - fixed system hard lock because of bug in the parser
- + * - codestyle fixes and less significant fixes
- + *
- + * based on ip_nat_irc.c
- + *
- + * This program is free software; you can redistribute it and/or
- + * modify it under the terms of the GNU General Public License
- + * as published by the Free Software Foundation; either version
- + * 2 of the License, or (at your option) any later version.
- + *
- + * Module load syntax:
- + * insmod nf_nat_rtsp.o ports=port1,port2,...port<MAX_PORTS>
- + * stunaddr=<address>
- + * destaction=[auto|strip|none]
- + *
- + * If no ports are specified, the default will be port 554 only.
- + *
- + * stunaddr specifies the address used to detect that a client is using STUN.
- + * If this address is seen in the destination parameter, it is assumed that
- + * the client has already punched a UDP hole in the firewall, so we don't
- + * mangle the client_port. If none is specified, it is autodetected. It
- + * only needs to be set if you have multiple levels of NAT. It should be
- + * set to the external address that the STUN clients detect. Note that in
- + * this case, it will not be possible for clients to use UDP with servers
- + * between the NATs.
- + *
- + * If no destaction is specified, auto is used.
- + * destaction=auto: strip destination parameter if it is not stunaddr.
- + * destaction=strip: always strip destination parameter (not recommended).
- + * destaction=none: do not touch destination parameter (not recommended).
- + */
- +
- +#include <linux/module.h>
- +#include <linux/version.h>
- +#include <net/tcp.h>
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- +# include <net/netfilter/nf_nat.h>
- +#else
- +# include <net/netfilter/nf_nat_rule.h>
- +#endif
- +#include <net/netfilter/nf_nat_helper.h>
- +#include "nf_conntrack_rtsp.h"
- +#include <net/netfilter/nf_conntrack_expect.h>
- +
- +#include <linux/inet.h>
- +#include <linux/ctype.h>
- +#define NF_NEED_STRNCASECMP
- +#define NF_NEED_STRTOU16
- +#include "netfilter_helpers.h"
- +#define NF_NEED_MIME_NEXTLINE
- +#include "netfilter_mime.h"
- +
- +#define MAX_PORTS 8
- +#define DSTACT_AUTO 0
- +#define DSTACT_STRIP 1
- +#define DSTACT_NONE 2
- +
- +static char* stunaddr = NULL;
- +static char* destaction = NULL;
- +
- +static u_int32_t extip = 0;
- +static int dstact = 0;
- +
- +static void nf_nat_rtsp_expected(struct nf_conn* ct, struct nf_conntrack_expect *exp);
- +
- +MODULE_AUTHOR("Tom Marshall <tmarshall at real.com>");
- +MODULE_DESCRIPTION("RTSP network address translation module");
- +MODULE_LICENSE("GPL");
- +module_param(stunaddr, charp, 0644);
- +MODULE_PARM_DESC(stunaddr, "Address for detecting STUN");
- +module_param(destaction, charp, 0644);
- +MODULE_PARM_DESC(destaction, "Action for destination parameter (auto/strip/none)");
- +
- +#define SKIP_WSPACE(ptr,len,off) while(off < len && isspace(*(ptr+off))) { off++; }
- +
- +/*** helper functions ***/
- +
- +static void
- +get_skb_tcpdata(struct sk_buff* skb, char** pptcpdata, uint* ptcpdatalen)
- +{
- + struct iphdr* iph = ip_hdr(skb);
- + struct tcphdr* tcph = (void *)iph + ip_hdrlen(skb);
- +
- + *pptcpdata = (char*)tcph + tcph->doff*4;
- + *ptcpdatalen = ((char*)skb_transport_header(skb) + skb->len) - *pptcpdata;
- +}
- +
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- +/* copy of sip_sprintf_addr */
- +static int rtsp_sprintf_addr(const struct nf_conn *ct, char *buffer,
- + const union nf_inet_addr *addr, bool delim)
- +{
- + if (nf_ct_l3num(ct) == NFPROTO_IPV4) {
- + return sprintf(buffer, "%pI4", &addr->ip);
- + } else {
- + if (delim)
- + return sprintf(buffer, "[%pI6c]", &addr->ip6);
- + else
- + return sprintf(buffer, "%pI6c", &addr->ip6);
- + }
- +}
- +#endif
- +
- +/*** nat functions ***/
- +
- +/*
- + * Mangle the "Transport:" header:
- + * - Replace all occurences of "client_port=<spec>"
- + * - Handle destination parameter
- + *
- + * In:
- + * ct, ctinfo = conntrack context
- + * skb = packet
- + * tranoff = Transport header offset from TCP data
- + * tranlen = Transport header length (incl. CRLF)
- + * rport_lo = replacement low port (host endian)
- + * rport_hi = replacement high port (host endian)
- + *
- + * Returns packet size difference.
- + *
- + * Assumes that a complete transport header is present, ending with CR or LF
- + */
- +static int
- +rtsp_mangle_tran(enum ip_conntrack_info ctinfo,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + unsigned int protoff,
- +#endif
- + struct nf_conntrack_expect* rtp_exp,
- + struct nf_conntrack_expect* rtcp_exp,
- + struct ip_ct_rtsp_expect* prtspexp,
- + struct sk_buff* skb, uint tranoff, uint tranlen)
- +{
- + char* ptcp;
- + uint tcplen;
- + char* ptran;
- + char rbuf1[16]; /* Replacement buffer (one port) */
- + uint rbuf1len; /* Replacement len (one port) */
- + char rbufa[16]; /* Replacement buffer (all ports) */
- + uint rbufalen; /* Replacement len (all ports) */
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + union nf_inet_addr newip;
- +#else
- + u_int32_t newip;
- +#endif
- + u_int16_t loport, hiport;
- + uint off = 0;
- + uint diff; /* Number of bytes we removed */
- +
- + struct nf_conn *ct = rtp_exp->master;
- + /* struct nf_conn *ct = nf_ct_get(skb, &ctinfo); */
- + struct nf_conntrack_tuple *rtp_t;
- +
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + char szextaddr[INET6_ADDRSTRLEN];
- +#else
- + char szextaddr[INET_ADDRSTRLEN];
- +#endif
- + uint extaddrlen;
- + int is_stun;
- +
- + get_skb_tcpdata(skb, &ptcp, &tcplen);
- + ptran = ptcp+tranoff;
- +
- + if (tranoff+tranlen > tcplen || tcplen-tranoff < tranlen ||
- + tranlen < 10 || !iseol(ptran[tranlen-1]) ||
- + nf_strncasecmp(ptran, "Transport:", 10) != 0) {
- + pr_info("sanity check failed\n");
- + return 0;
- + }
- + off += 10;
- + SKIP_WSPACE(ptcp+tranoff, tranlen, off);
- +
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3;
- + rtp_t = &rtp_exp->tuple;
- + rtp_t->dst.u3 = newip;
- + if (rtcp_exp) {
- + rtcp_exp->tuple.dst.u3 = newip;
- + }
- + extaddrlen = rtsp_sprintf_addr(ct, szextaddr, &newip, true); // FIXME handle extip
- + pr_debug("stunaddr=%s (auto)\n", szextaddr);
- +#else
- + newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
- + rtp_t = &rtp_exp->tuple;
- + rtp_t->dst.u3.ip = newip;
- + if (rtcp_exp) {
- + rtcp_exp->tuple.dst.u3.ip = newip;
- + }
- + extaddrlen = extip ? sprintf(szextaddr, "%pI4", &extip)
- + : sprintf(szextaddr, "%pI4", &newip);
- + pr_debug("stunaddr=%s (%s)\n", szextaddr, (extip?"forced":"auto"));
- +#endif
- + hiport = 0;
- + rbuf1len = rbufalen = 0;
- + switch (prtspexp->pbtype) {
- + case pb_single:
- + for (loport = prtspexp->loport; loport != 0; loport++) { /* XXX: improper wrap? */
- + rtp_t->dst.u.udp.port = htons(loport);
- + if (nf_ct_expect_related(rtp_exp) == 0) {
- + pr_debug("using port %hu\n", loport);
- + break;
- + }
- + }
- + if (loport != 0) {
- + rbuf1len = sprintf(rbuf1, "%hu", loport);
- + rbufalen = sprintf(rbufa, "%hu", loport);
- + }
- + break;
- + case pb_range:
- + for (loport = prtspexp->loport; loport != 0; loport += 2) { /* XXX: improper wrap? */
- + rtp_t->dst.u.udp.port = htons(loport);
- + if (nf_ct_expect_related(rtp_exp) != 0) {
- + continue;
- + }
- + hiport = loport + 1;
- + rtcp_exp->tuple.dst.u.udp.port = htons(hiport);
- + if (nf_ct_expect_related(rtcp_exp) != 0) {
- + nf_ct_unexpect_related(rtp_exp);
- + continue;
- + }
- +
- + /* FIXME: invalid print in case of ipv6 */
- + pr_debug("nat expect_related %pI4:%u-%u-%pI4:%u-%u\n",
- + &rtp_exp->tuple.src.u3.ip,
- + ntohs(rtp_exp->tuple.src.u.udp.port),
- + ntohs(rtcp_exp->tuple.src.u.udp.port),
- + &rtp_exp->tuple.dst.u3.ip,
- + ntohs(rtp_exp->tuple.dst.u.udp.port),
- + ntohs(rtcp_exp->tuple.dst.u.udp.port));
- + break;
- + }
- + if (loport != 0) {
- + rbuf1len = sprintf(rbuf1, "%hu", loport);
- + rbufalen = sprintf(rbufa, "%hu-%hu", loport, hiport);
- + }
- + break;
- + case pb_discon:
- + for (loport = prtspexp->loport; loport != 0; loport++) { /* XXX: improper wrap? */
- + rtp_t->dst.u.udp.port = htons(loport);
- + if (nf_ct_expect_related(rtp_exp) == 0) {
- + pr_debug("using port %hu (1 of 2)\n", loport);
- + break;
- + }
- + }
- + for (hiport = prtspexp->hiport; hiport != 0; hiport++) { /* XXX: improper wrap? */
- + rtp_t->dst.u.udp.port = htons(hiport);
- + if (nf_ct_expect_related(rtp_exp) == 0) {
- + pr_debug("using port %hu (2 of 2)\n", hiport);
- + break;
- + }
- + }
- + if (loport != 0 && hiport != 0) {
- + rbuf1len = sprintf(rbuf1, "%hu", loport);
- + rbufalen = sprintf(rbufa, hiport == loport+1 ?
- + "%hu-%hu":"%hu/%hu", loport, hiport);
- + }
- + break;
- + }
- +
- + if (rbuf1len == 0)
- + return 0; /* cannot get replacement port(s) */
- +
- + /* Transport: tran;field;field=val,tran;field;field=val,...
- + `off` is set to the start of Transport value from start of line
- + */
- + while (off < tranlen) {
- + uint saveoff;
- + const char* pparamend;
- + uint nextparamoff;
- +
- + pparamend = memchr(ptran+off, ',', tranlen-off);
- + pparamend = (pparamend == NULL) ? ptran+tranlen : pparamend+1;
- + nextparamoff = pparamend-ptran;
- +
- + /*
- + * We pass over each param twice. On the first pass, we look for a
- + * destination= field. It is handled by the security policy. If it
- + * is present, allowed, and equal to our external address, we assume
- + * that STUN is being used and we leave the client_port= field alone.
- + */
- + is_stun = 0;
- + saveoff = off;
- + while (off < nextparamoff) {
- + const char* pfieldend;
- + uint nextfieldoff;
- +
- + pfieldend = memchr(ptran+off, ';', nextparamoff-off);
- + nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
- +
- + if (dstact != DSTACT_NONE && strncmp(ptran+off, "destination=", 12) == 0) {
- + if (strncmp(ptran+off+12, szextaddr, extaddrlen) == 0)
- + is_stun = 1;
- +
- + if (dstact == DSTACT_STRIP || (dstact == DSTACT_AUTO && !is_stun)) {
- + uint dstoff = (ptran-ptcp)+off;
- + uint dstlen = nextfieldoff-off;
- + char* pdstrep = NULL;
- + uint dstreplen = 0;
- + diff = dstlen;
- + if (dstact == DSTACT_AUTO && !is_stun) {
- + pr_debug("RTSP: replace dst addr\n");
- + dstoff += 12;
- + dstlen -= 13;
- + pdstrep = szextaddr;
- + dstreplen = extaddrlen;
- + diff = nextfieldoff-off-13-extaddrlen;
- + }
- +
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff,
- + dstoff, dstlen, pdstrep, dstreplen)) {
- +#else
- + if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
- + dstoff, dstlen, pdstrep, dstreplen)) {
- +#endif
- + /* mangle failed, all we can do is bail */
- + nf_ct_unexpect_related(rtp_exp);
- + if (rtcp_exp)
- + nf_ct_unexpect_related(rtcp_exp);
- + return 0;
- + }
- + get_skb_tcpdata(skb, &ptcp, &tcplen);
- + ptran = ptcp+tranoff;
- + tranlen -= diff;
- + nextparamoff -= diff;
- + nextfieldoff -= diff;
- + }
- + }
- +
- + off = nextfieldoff;
- + }
- +
- + if (is_stun)
- + continue;
- +
- + off = saveoff;
- + while (off < nextparamoff) {
- + const char* pfieldend;
- + uint nextfieldoff;
- +
- + pfieldend = memchr(ptran+off, ';', nextparamoff-off);
- + nextfieldoff = (pfieldend == NULL) ? nextparamoff : pfieldend-ptran+1;
- +
- + if (strncmp(ptran+off, "client_port=", 12) == 0) {
- + u_int16_t port;
- + uint numlen;
- + uint origoff;
- + uint origlen;
- + char* rbuf = rbuf1;
- + uint rbuflen = rbuf1len;
- +
- + off += 12;
- + origoff = (ptran-ptcp)+off;
- + origlen = 0;
- + numlen = nf_strtou16(ptran+off, &port);
- + off += numlen;
- + origlen += numlen;
- + if (port != prtspexp->loport) {
- + pr_debug("multiple ports found, port %hu ignored\n", port);
- + } else {
- + if (ptran[off] == '-' || ptran[off] == '/') {
- + off++;
- + origlen++;
- + numlen = nf_strtou16(ptran+off, &port);
- + off += numlen;
- + origlen += numlen;
- + rbuf = rbufa;
- + rbuflen = rbufalen;
- + }
- +
- + /*
- + * note we cannot just memcpy() if the sizes are the same.
- + * the mangle function does skb resizing, checks for a
- + * cloned skb, and updates the checksums.
- + *
- + * parameter 4 below is offset from start of tcp data.
- + */
- + diff = origlen-rbuflen;
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff,
- + origoff, origlen, rbuf, rbuflen)) {
- +#else
- + if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
- + origoff, origlen, rbuf, rbuflen)) {
- +#endif
- + /* mangle failed, all we can do is bail */
- + nf_ct_unexpect_related(rtp_exp);
- + if (rtcp_exp)
- + nf_ct_unexpect_related(rtcp_exp);
- + return 0;
- + }
- + get_skb_tcpdata(skb, &ptcp, &tcplen);
- + ptran = ptcp+tranoff;
- + tranlen -= diff;
- + nextparamoff -= diff;
- + nextfieldoff -= diff;
- + }
- + }
- +
- + off = nextfieldoff;
- + }
- +
- + off = nextparamoff;
- + }
- +
- + return 1;
- +}
- +
- +static uint
- +help_out(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + unsigned int protoff,
- +#endif
- + unsigned int matchoff, unsigned int matchlen,
- + struct ip_ct_rtsp_expect* prtspexp,
- + struct nf_conntrack_expect* rtp_exp,
- + struct nf_conntrack_expect* rtcp_exp)
- +{
- + char* ptcp;
- + uint tcplen;
- + uint hdrsoff;
- + uint hdrslen;
- + uint lineoff;
- + uint linelen;
- + uint off;
- + int dir = CTINFO2DIR(ctinfo);
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + union nf_inet_addr saddr = rtp_exp->master->tuplehash[dir].tuple.src.u3;
- +#else
- + __be32 saddr = rtp_exp->master->tuplehash[dir].tuple.src.u3.ip;
- +#endif
- +
- + //struct iphdr* iph = (struct iphdr*)(*pskb)->nh.iph;
- + //struct tcphdr* tcph = (struct tcphdr*)((void*)iph + iph->ihl*4);
- +
- + get_skb_tcpdata(skb, &ptcp, &tcplen);
- + hdrsoff = matchoff;//exp->seq - ntohl(tcph->seq);
- + hdrslen = matchlen;
- + off = hdrsoff;
- + pr_debug("NAT rtsp help_out\n");
- +
- + while (nf_mime_nextline(ptcp, hdrsoff+hdrslen, &off, &lineoff, &linelen)) {
- + if (linelen == 0)
- + break;
- +
- + if (off > hdrsoff+hdrslen) {
- + pr_info("!! overrun !!");
- + break;
- + }
- + pr_debug("hdr: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
- +
- + if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0) {
- + uint oldtcplen = tcplen;
- + pr_debug("hdr: Transport\n");
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + if (!rtsp_mangle_tran(ctinfo, protoff, rtp_exp, rtcp_exp,
- + prtspexp, skb, lineoff, linelen)) {
- +#else
- + if (!rtsp_mangle_tran(ctinfo, rtp_exp, rtcp_exp, prtspexp,
- + skb, lineoff, linelen)) {
- +#endif
- + pr_debug("hdr: Transport mangle failed");
- + break;
- + }
- + rtp_exp->expectfn = nf_nat_rtsp_expected;
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + rtp_exp->saved_addr = saddr;
- +#else
- + rtp_exp->saved_ip = saddr;
- +#endif
- + rtp_exp->saved_proto.udp.port = htons(prtspexp->loport);
- + rtp_exp->dir = !dir;
- + if (rtcp_exp) {
- + rtcp_exp->expectfn = nf_nat_rtsp_expected;
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + rtcp_exp->saved_addr = saddr;
- +#else
- + rtcp_exp->saved_ip = saddr;
- +#endif
- + rtcp_exp->saved_proto.udp.port = htons(prtspexp->hiport);
- + rtcp_exp->dir = !dir;
- + }
- + get_skb_tcpdata(skb, &ptcp, &tcplen);
- + hdrslen -= (oldtcplen-tcplen);
- + off -= (oldtcplen-tcplen);
- + lineoff -= (oldtcplen-tcplen);
- + linelen -= (oldtcplen-tcplen);
- + pr_debug("rep: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff);
- + }
- + }
- +
- + return NF_ACCEPT;
- +}
- +
- +static unsigned int
- +nf_nat_rtsp(struct sk_buff *skb, enum ip_conntrack_info ctinfo,
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + unsigned int protoff,
- +#endif
- + unsigned int matchoff, unsigned int matchlen,
- + struct ip_ct_rtsp_expect* prtspexp,
- + struct nf_conntrack_expect* rtp_exp,
- + struct nf_conntrack_expect* rtcp_exp)
- +{
- + int dir = CTINFO2DIR(ctinfo);
- + int rc = NF_ACCEPT;
- +
- + switch (dir) {
- + case IP_CT_DIR_ORIGINAL:
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + rc = help_out(skb, ctinfo, protoff, matchoff, matchlen, prtspexp,
- + rtp_exp, rtcp_exp);
- +#else
- + rc = help_out(skb, ctinfo, matchoff, matchlen, prtspexp,
- + rtp_exp, rtcp_exp);
- +#endif
- + break;
- + case IP_CT_DIR_REPLY:
- + pr_debug("unmangle ! %u\n", ctinfo);
- + /* XXX: unmangle */
- + rc = NF_ACCEPT;
- + break;
- + }
- + //UNLOCK_BH(&ip_rtsp_lock);
- +
- + return rc;
- +}
- +
- +static void nf_nat_rtsp_expected(struct nf_conn* ct, struct nf_conntrack_expect *exp)
- +{
- +#if LINUX_VERSION_CODE < KERNEL_VERSION(3,3,0) || LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + struct nf_nat_range range;
- +#else
- + struct nf_nat_ipv4_range range;
- +#endif
- +
- + /* This must be a fresh one. */
- + BUG_ON(ct->status & IPS_NAT_DONE_MASK);
- +
- + /* For DST manip, map port here to where it's expected. */
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + range.min_proto = range.max_proto = exp->saved_proto;
- + range.min_addr = range.max_addr = exp->saved_addr;
- +#else
- + range.min = range.max = exp->saved_proto;
- + range.min_ip = range.max_ip = exp->saved_ip;
- +#endif
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,3,0)
- + range.flags = (NF_NAT_RANGE_MAP_IPS | NF_NAT_RANGE_PROTO_SPECIFIED);
- + nf_nat_setup_info(ct, &range, NF_NAT_MANIP_DST);
- +#else
- + range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED);
- + nf_nat_setup_info(ct, &range, IP_NAT_MANIP_DST);
- +#endif
- +
- + /* Change src to where master sends to, but only if the connection
- + * actually came from the same source. */
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,7,0)
- + if (nf_inet_addr_cmp(&ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3,
- + &ct->master->tuplehash[exp->dir].tuple.src.u3)) {
- + range.min_addr = range.max_addr
- + = ct->master->tuplehash[!exp->dir].tuple.dst.u3;
- +#else
- + if (ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip ==
- + ct->master->tuplehash[exp->dir].tuple.src.u3.ip) {
- + range.min_ip = range.max_ip
- + = ct->master->tuplehash[!exp->dir].tuple.dst.u3.ip;
- +#endif
- +#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,3,0)
- + range.flags = NF_NAT_RANGE_MAP_IPS;
- + nf_nat_setup_info(ct, &range, NF_NAT_MANIP_SRC);
- +#else
- + range.flags = IP_NAT_RANGE_MAP_IPS;
- + nf_nat_setup_info(ct, &range, IP_NAT_MANIP_SRC);
- +#endif
- + }
- +}
- +
- +
- +static void __exit fini(void)
- +{
- + rcu_assign_pointer(nf_nat_rtsp_hook, NULL);
- + synchronize_net();
- +}
- +
- +static int __init init(void)
- +{
- + printk("nf_nat_rtsp v" IP_NF_RTSP_VERSION " loading\n");
- +
- + BUG_ON(nf_nat_rtsp_hook);
- + rcu_assign_pointer(nf_nat_rtsp_hook, nf_nat_rtsp);
- +
- + if (stunaddr != NULL)
- + extip = in_aton(stunaddr);
- +
- + if (destaction != NULL) {
- + if (strcmp(destaction, "auto") == 0)
- + dstact = DSTACT_AUTO;
- +
- + if (strcmp(destaction, "strip") == 0)
- + dstact = DSTACT_STRIP;
- +
- + if (strcmp(destaction, "none") == 0)
- + dstact = DSTACT_NONE;
- + }
- +
- + return 0;
- +}
- +
- +module_init(init);
- +module_exit(fini);
- --- a/extensions/Kbuild
- +++ b/extensions/Kbuild
- @@ -26,6 +26,7 @@ obj-${build_lscan} += xt_lscan.o
- obj-${build_pknock} += pknock/
- obj-${build_psd} += xt_psd.o
- obj-${build_quota2} += xt_quota2.o
- +obj-${build_rtsp} += rtsp/
-
- -include ${M}/*.Kbuild
- -include ${M}/Kbuild.*
- --- a/mconfig
- +++ b/mconfig
- @@ -22,3 +22,4 @@ build_lscan=m
- build_pknock=m
- build_psd=m
- build_quota2=m
- +build_rtsp=m
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