--- linux-2.6.19/include/linux/netfilter_helpers.h +++ linux-2.6.19/include/linux/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 +#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 */ --- linux-2.6.19/include/linux/netfilter_ipv4/ip_conntrack_rtsp.h +++ linux-2.6.19/include/linux/netfilter_ipv4/ip_conntrack_rtsp.h @@ -0,0 +1,62 @@ +/* + * RTSP extension for IP connection tracking. + * (C) 2003 by Tom Marshall + * 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. + */ +#ifndef _IP_CONNTRACK_RTSP_H +#define _IP_CONNTRACK_RTSP_H + +/* #define IP_NF_RTSP_DEBUG */ +#define IP_NF_RTSP_VERSION "0.6.22" + +/* 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 */ +#if 0 + uint method; /* RTSP method */ + uint cseq; /* CSeq from request */ +#endif +}; + +#ifdef __KERNEL__ +extern unsigned int (*ip_nat_rtsp_hook)(struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + unsigned int matchoff, + unsigned int matchlen, + struct ip_ct_rtsp_expect *expinfo, + struct ip_conntrack_expect *exp); + +#define RTSP_PORT 554 + +#endif /* __KERNEL__ */ + +#endif /* _IP_CONNTRACK_RTSP_H */ --- linux-2.6.19/include/linux/netfilter_mime.h +++ linux-2.6.19/include/linux/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 + +/* + * 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 */ --- linux-2.6.19/net/ipv4/netfilter/ip_conntrack_rtsp.c +++ linux-2.6.19/net/ipv4/netfilter/ip_conntrack_rtsp.c @@ -0,0 +1,577 @@ +/* + * RTSP extension for IP connection tracking + * (C) 2003 by Tom Marshall + * 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 ip_conntrack_rtsp.o ports=port1,port2,...port + * 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). + * + * 2005-02-13: Harald Welte + * - port to 2.6 + * - update to recent post-2.6.11 api changes + * + * 2010-02-05: Mario Leibezeder + * - update to 2.6.13.1 (avm fritzbox 7170) + * - patch for aontv rtsp servers + */ + +//#include +#include +#include +#include +#include +#include + +#include +#include + +#include +#define NF_NEED_STRNCASECMP +#define NF_NEED_STRTOU16 +#define NF_NEED_STRTOU32 +#define NF_NEED_NEXTLINE +#include +#define NF_NEED_MIME_NEXTLINE +#include + +#define MAX_SIMUL_SETUP 8 /* XXX: use max_outstanding */ + +#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args) +#ifdef IP_NF_RTSP_DEBUG +#define DEBUGP(fmt, args...) printk(KERN_DEBUG "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args) +#else +#define DEBUGP(fmt, args...) +#endif + +#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 "); +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[65536]; +static DEFINE_SPINLOCK(rtsp_buffer_lock); + +unsigned int (*ip_nat_rtsp_hook)(struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + unsigned int matchoff, + unsigned int matchlen, + struct ip_ct_rtsp_expect *expinfo, + struct ip_conntrack_expect *exp); +EXPORT_SYMBOL_GPL(ip_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 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) + { + INFOP("!! overrun !!\n"); + break; + } + + if (nf_strncasecmp(ptcp+lineoff, "CSeq:", 5) == 0) + { + *pcseqoff = lineoff; + *pcseqlen = 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 (if any) in transport header + * In: + * ptcp, tcplen = packet + * tranoff, tranlen = buffer to search + * + * Out: + * pport_lo, pport_hi = lo/hi ports (host endian) + * + * 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) + { + INFOP("sanity check failed\n"); + return 0; + } + DEBUGP("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; + const char* pdestport; + 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) + { + DEBUGP("multiple ports found, port %hu ignored\n", port); + } + else + { + 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) + { + DEBUGP("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; + } + } + // AONTV Patch: read client port from "destination=IP:Port" parameter + else if ((strncmp(ptran+off, "destination=",12) == 0) && ((pdestport = memchr(ptran+off, ':', nextparamoff-off)) != NULL)) + { + u_int16_t port; + uint numlen; + + off += 12; + + pdestport++; + + off = pdestport - ptran; + numlen = nf_strtou16(ptran + off, &port); + off += numlen; + + if (prtspexp->loport != 0 && prtspexp->loport != port) + { + DEBUGP("multiple ports found, port %hu ignored\n", port); + } + else + { + DEBUGP("destination port %hu found\n", port); + + prtspexp->pbtype = pb_single; + prtspexp->loport = port; + prtspexp->hiport = port; + + rc = 1; + } + } + + off = nextfieldoff; + } + + off = nextparamoff; + } + + return rc; +} + +/*** conntrack functions ***/ + +/* outbound packet: client->server */ +static inline int +help_out(struct sk_buff **pskb, unsigned char *rb_ptr, unsigned int datalen, + struct ip_conntrack* ct, enum ip_conntrack_info ctinfo) +{ + 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 ip_conntrack_expect *exp; + + memset(&expinfo, 0, sizeof(expinfo)); + + while (dataoff < datalen) + { + uint cmdoff = dataoff; + uint hdrsoff = 0; + uint hdrslen = 0; + uint cseqoff = 0; + uint cseqlen = 0; + uint lineoff = 0; + uint linelen = 0; + uint off; + + if (!rtsp_parse_message(pdata, datalen, &dataoff, + &hdrsoff, &hdrslen, + &cseqoff, &cseqlen)) + { + break; /* not a valid message */ + } + + if (strncmp(pdata+cmdoff, "SETUP ", 6) != 0) + { + continue; /* not a SETUP message */ + } + DEBUGP("found a setup message\n"); + + off = 0; + while (nf_mime_nextline(pdata+hdrsoff, hdrslen, &off, + &lineoff, &linelen)) + { + if (linelen == 0) + { + break; + } + if (off > hdrsoff+hdrslen) + { + INFOP("!! overrun !!"); + break; + } + + if (nf_strncasecmp(pdata+hdrsoff+lineoff, "Transport:", 10) == 0) + { + rtsp_parse_transport(pdata+hdrsoff+lineoff, linelen, &expinfo); + } + } + + if (expinfo.loport == 0) + { + DEBUGP("no udp transports found\n"); + continue; /* no udp transports found */ + } + + DEBUGP("udp transport found, ports=(%d,%hu,%hu)\n", + (int)expinfo.pbtype, + expinfo.loport, + expinfo.hiport); + + exp = ip_conntrack_expect_alloc(ct); + if (!exp) { + ret = NF_DROP; + goto out; + } + + //exp->seq = ntohl(tcph->seq) + hdrsoff; /* mark all the headers */ + //exp->master = ct; + //exp.help.exp_rtsp_info.len = hdrslen; + + // set expected server IP to 255.255.255.0 subnet in case of multiple rtsp server ip's + exp->tuple.src.ip = ct->tuplehash[!dir].tuple.src.ip & 0x00ffffff; + exp->mask.src.ip = 0x00ffffff; + exp->tuple.dst.ip = ct->tuplehash[dir].tuple.src.ip; + exp->mask.dst.ip = 0xffffffff; + exp->tuple.src.u.udp.port = 0; + exp->mask.src.u.udp.port = 0x0000; + exp->tuple.dst.u.udp.port = htons(expinfo.loport); + exp->mask.dst.u.udp.port = (expinfo.pbtype == pb_range) ? 0xfffe : 0xffff; + exp->tuple.dst.protonum = IPPROTO_UDP; + exp->mask.dst.protonum = 0xff; + exp->expectfn = NULL; + + DEBUGP("expect_related %u.%u.%u.%u:%u mask %u.%u.%u.%u -> %u.%u.%u.%u:%u mask %u.%u.%u.%u\n", + NIPQUAD(exp->tuple.src.ip), + ntohs(exp->tuple.src.u.udp.port), + NIPQUAD(exp->mask.src.ip), + NIPQUAD(exp->tuple.dst.ip), + ntohs(exp->tuple.dst.u.udp.port), + NIPQUAD(exp->mask.dst.ip)); + + if (ip_nat_rtsp_hook) + /* pass the request off to the nat helper */ + ret = ip_nat_rtsp_hook(pskb, ctinfo, hdrsoff,hdrslen,&expinfo, exp); + else if (ip_conntrack_expect_related(exp) != 0) { + INFOP("ip_conntrack_expect_related failed\n"); + //ip_conntrack_expect_free(exp); + ret = NF_DROP; + } + + DEBUGP("expect_related %u.%u.%u.%u:%u mask %u.%u.%u.%u -> %u.%u.%u.%u:%u mask %u.%u.%u.%u\n", + NIPQUAD(exp->tuple.src.ip), + ntohs(exp->tuple.src.u.udp.port), + NIPQUAD(exp->mask.src.ip), + NIPQUAD(exp->tuple.dst.ip), + ntohs(exp->tuple.dst.u.udp.port), + NIPQUAD(exp->mask.dst.ip)); + + ip_conntrack_expect_put(exp); + goto out; + } + +out: + + return ret; +} + +/* inbound packet: server->client */ +static inline int +help_in(struct sk_buff **pskb, size_t pktlen, + struct ip_conntrack* ct, enum ip_conntrack_info ctinfo) +{ + return NF_ACCEPT; +} + +static int help(struct sk_buff **pskb, struct ip_conntrack* 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) + { + DEBUGP("conntrackinfo = %u\n", ctinfo); + return NF_ACCEPT; + } + + /* Not whole TCP header? */ + th = skb_header_pointer(*pskb, (*pskb)->nh.iph->ihl*4, + sizeof(_tcph), &_tcph); + if (!th) + return NF_ACCEPT; + + /* No data ? */ + dataoff = (*pskb)->nh.iph->ihl*4 + th->doff*4; + datalen = (*pskb)->len - dataoff; + if (dataoff >= (*pskb)->len) + return NF_ACCEPT; + + spin_lock_bh(&rtsp_buffer_lock); + rb_ptr = skb_header_pointer(*pskb, dataoff, + (*pskb)->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: + ret = help_out(pskb, rb_ptr, datalen, ct, ctinfo); + break; + case IP_CT_DIR_REPLY: + /* inbound packet: server->client */ + ret = NF_ACCEPT; + break; + } + + spin_unlock_bh(&rtsp_buffer_lock); + + return ret; +} + +static struct ip_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++) + { + DEBUGP("unregistering port %d\n", ports[i]); + ip_conntrack_helper_unregister(&rtsp_helpers[i]); + } +} + +static int __init +init(void) +{ + int i, ret; + struct ip_conntrack_helper *hlpr; + char *tmpname; + + printk("ip_conntrack_rtsp v" IP_NF_RTSP_VERSION " loading\n"); + + if (max_outstanding < 1) + { + printk("ip_conntrack_rtsp: max_outstanding must be a positive integer\n"); + return -EBUSY; + } + if (setup_timeout < 0) + { + printk("ip_conntrack_rtsp: setup_timeout must be a positive integer\n"); + return -EBUSY; + } + + /* If no port given, default to standard rtsp port */ + if (ports[0] == 0) + { + ports[0] = RTSP_PORT; + } + + for (i = 0; (i < MAX_PORTS) && ports[i]; i++) + { + hlpr = &rtsp_helpers[i]; + memset(hlpr, 0, sizeof(struct ip_conntrack_helper)); + hlpr->tuple.src.u.tcp.port = htons(ports[i]); + hlpr->tuple.dst.protonum = IPPROTO_TCP; + hlpr->mask.src.u.tcp.port = 0xFFFF; + hlpr->mask.dst.protonum = 0xFF; + hlpr->max_expected = max_outstanding; + hlpr->timeout = setup_timeout; + 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); + } + hlpr->name = tmpname; + + DEBUGP("port #%d: %d\n", i, ports[i]); + + ret = ip_conntrack_helper_register(hlpr); + + if (ret) + { + printk("ip_conntrack_rtsp: ERROR registering port %d\n", ports[i]); + fini(); + return -EBUSY; + } + num_ports++; + } + return 0; +} + +module_init(init); +module_exit(fini); --- linux-2.6.19/net/ipv4/netfilter/ip_nat_rtsp.c +++ linux-2.6.19/net/ipv4/netfilter/ip_nat_rtsp.c @@ -0,0 +1,585 @@ +/* + * RTSP extension for TCP NAT alteration + * (C) 2003 by Tom Marshall + * 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 ip_nat_rtsp.o ports=port1,port2,...port + * stunaddr=
+ * 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 +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include +#include +#define NF_NEED_STRNCASECMP +#define NF_NEED_STRTOU16 +#include +#define NF_NEED_MIME_NEXTLINE +#include + +#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args) +#ifdef IP_NF_RTSP_DEBUG +#define DEBUGP(fmt, args...) printk(KERN_DEBUG "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args) +#else +#define DEBUGP(fmt, args...) +#endif + +#define MAX_PORTS 8 +#define DSTACT_AUTO 0 +#define DSTACT_STRIP 1 +#define DSTACT_NONE 2 + +//static int ports[MAX_PORTS]; +static char* stunaddr = NULL; +static char* destaction = NULL; + +//static int num_ports = 0; +static u_int32_t extip = 0; +static int dstact = 0; + +MODULE_AUTHOR("Tom Marshall "); +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 = (struct iphdr*)skb->nh.iph; + struct tcphdr* tcph = (struct tcphdr*)((char*)iph + iph->ihl*4); + + *pptcpdata = (char*)tcph + tcph->doff*4; + *ptcpdatalen = ((char*)skb->h.raw + skb->len) - *pptcpdata; +} + +/*** nat functions ***/ + +/* + * Mangle the "Transport:" header: + * - Replace all occurences of "client_port=" + * - Handle destination parameter + * + * In: + * ct, ctinfo = conntrack context + * pskb = 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, + struct ip_conntrack_expect* exp, + struct ip_ct_rtsp_expect* prtspexp, + struct sk_buff** pskb, 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) */ + u_int32_t newip; + u_int16_t loport, hiport; + uint off = 0; + uint diff; /* Number of bytes we removed */ + + struct ip_conntrack *ct = exp->master; + struct ip_conntrack_tuple* t; + + char szextaddr[15+1]; + uint extaddrlen; + int is_stun; + + get_skb_tcpdata(*pskb, &ptcp, &tcplen); + ptran = ptcp+tranoff; + + if (tranoff+tranlen > tcplen || tcplen-tranoff < tranlen || + tranlen < 10 || !iseol(ptran[tranlen-1]) || + nf_strncasecmp(ptran, "Transport:", 10) != 0) + { + INFOP("sanity check failed\n"); + return 0; + } + off += 10; + SKIP_WSPACE(ptcp+tranoff, tranlen, off); + + newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.ip; + t = &(exp->tuple); + t->dst.ip = newip; + + extaddrlen = extip ? sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(extip)) + : sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(newip)); + DEBUGP("stunaddr=%s (%s)\n", szextaddr, (extip?"forced":"auto")); + + rbuf1len = rbufalen = 0; + switch (prtspexp->pbtype) + { + case pb_single: + for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */ + { + t->dst.u.udp.port = htons(loport); + if (ip_conntrack_expect_related(exp) == 0) + { + DEBUGP("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? */ + { + t->dst.u.udp.port = htons(loport); + if (ip_conntrack_expect_related(exp) == 0) + { + hiport = loport + ~exp->mask.dst.u.udp.port; + DEBUGP("using ports %hu-%hu\n", loport, hiport); + break; + } + } + if (loport != 0) + { + rbuf1len = sprintf(rbuf1, "%hu", loport); + rbufalen = sprintf(rbufa, "%hu-%hu", loport, loport+1); + } + break; + case pb_discon: + for (loport = prtspexp->loport; loport != 0; loport++) /* XXX: improper wrap? */ + { + t->dst.u.udp.port = htons(loport); + if (ip_conntrack_expect_related(exp) == 0) + { + DEBUGP("using port %hu (1 of 2)\n", loport); + break; + } + } + for (hiport = prtspexp->hiport; hiport != 0; hiport++) /* XXX: improper wrap? */ + { + t->dst.u.udp.port = htons(hiport); + if (ip_conntrack_expect_related(exp) == 0) + { + DEBUGP("using port %hu (2 of 2)\n", hiport); + break; + } + } + if (loport != 0 && hiport != 0) + { + rbuf1len = sprintf(rbuf1, "%hu", loport); + if (hiport == loport+1) + { + rbufalen = sprintf(rbufa, "%hu-%hu", loport, hiport); + } + else + { + rbufalen = sprintf(rbufa, "%hu/%hu", loport, hiport); + } + } + break; + } + + if (rbuf1len == 0) + { + return 0; /* cannot get replacement port(s) */ + } + + /* Transport: tran;field;field=val,tran;field;field=val,... */ + 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-ptcp; + + /* + * 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)) + { + diff = nextfieldoff-off; + if (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, + off, diff, NULL, 0)) + { + // mangle failed, all we can do is bail + ip_conntrack_unexpect_related(exp); + return 0; + } + get_skb_tcpdata(*pskb, &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; + const char* pdestport; + 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) + { + DEBUGP("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 (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, + origoff, origlen, rbuf, rbuflen)) + { + /* mangle failed, all we can do is bail */ + ip_conntrack_unexpect_related(exp); + return 0; + } + get_skb_tcpdata(*pskb, &ptcp, &tcplen); + ptran = ptcp+tranoff; + tranlen -= diff; + nextparamoff -= diff; + nextfieldoff -= diff; + } + } + // AONTV Patch: read client port from "destination=IP:Port" parameter + else if ((strncmp(ptran+off, "destination=", 12) == 0) && ((pdestport = memchr(ptran+off+12, ':', nextparamoff-(off + 12))) != NULL)) + { + u_int16_t port; + uint numlen; + uint origoff; + uint origlen; + char rbuf[32]; + uint rbuflen = sprintf(rbuf, "%s:%s",szextaddr,rbuf1); + + pdestport++; + + off += 12; + origoff = (ptran + off) - ptcp; + origlen = pdestport - (ptran + off); + + off += origlen; + + numlen = nf_strtou16(ptran+off, &port); + off += numlen; + origlen += numlen; + + if (port != prtspexp->loport) + { + DEBUGP("multiple ports found, port %hu ignored\n", port); + } + else + { + diff = origlen-rbuflen; + if (!ip_nat_mangle_tcp_packet(pskb, ct, ctinfo, + origoff, origlen, rbuf, rbuflen)) + { + /* mangle failed, all we can do is bail */ + ip_conntrack_unexpect_related(exp); + return 0; + } + get_skb_tcpdata(*pskb, &ptcp, &tcplen); + ptran = ptcp+tranoff; + tranlen -= diff; + nextparamoff -= diff; + nextfieldoff -= diff; + } + } + + + off = nextfieldoff; + } + + off = nextparamoff; + } + + return 1; +} + + +static void +expected(struct ip_conntrack *ct, + struct ip_conntrack_expect *exp) +{ + struct ip_nat_range range; + u_int32_t newdstip, newsrcip, newip; + u_int16_t newdstport, newsrcport, newport; + + + /* This must be a fresh one. */ + //BUG_ON(ct->status & IPS_NAT_DONE_MASK); + + newdstip = ct->master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; + newdstport = ct->master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; + newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.ip; + newsrcport = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u.udp.port; + //FIXME (how to port that ?) + //code from 2.4 : newip = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC) ? newsrcip : newdstip; + newip = newdstip; + newport = exp->saved_proto.udp.port; + + DEBUGP("newsrcip=%u.%u.%u.%u:%u, newdstip=%u.%u.%u.%u:%u, newip=%u.%u.%u.%u:%u\n", + NIPQUAD(newsrcip),ntohs(newsrcport),NIPQUAD(newdstip),ntohs(newdstport),NIPQUAD(newip),ntohs(newport)); + + + /* For DST manip, map port here to where it's expected. */ + range.flags = (IP_NAT_RANGE_MAP_IPS | IP_NAT_RANGE_PROTO_SPECIFIED); + range.min = range.max = exp->saved_proto; + range.min_ip = range.max_ip = newip; + + + /* hook doesn't matter, but it has to do destination manip */ + ip_nat_setup_info(ct, &range, NF_IP_PRE_ROUTING); +} + + + +static unsigned int +help_out(struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + unsigned int matchoff, + unsigned int matchlen, + struct ip_ct_rtsp_expect* prtspexp, + struct ip_conntrack_expect *exp) +{ + char* ptcp; + uint tcplen; + uint hdrsoff; + uint hdrslen; + uint lineoff; + uint linelen; + uint off; + + //struct iphdr* iph = (struct iphdr*)(*pskb)->nh.iph; + //struct tcphdr* tcph = (struct tcphdr*)((void*)iph + iph->ihl*4); + + get_skb_tcpdata(*pskb, &ptcp, &tcplen); + hdrsoff = matchoff;//exp->seq - ntohl(tcph->seq); + hdrslen = matchlen;//prtspexp->len; + off = hdrsoff; + + DEBUGP("NAT rtsp help_out\n"); + + while (nf_mime_nextline(ptcp, hdrsoff+hdrslen, &off, &lineoff, &linelen)) + { + if (linelen == 0) + { + break; + } + if (off > hdrsoff+hdrslen) + { + INFOP("!! overrun !!"); + break; + } + DEBUGP("hdr: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff); + + + if (nf_strncasecmp(ptcp+lineoff, "Transport:", 10) == 0) + { + uint oldtcplen = tcplen; + DEBUGP("hdr: Transport\n"); + if (!rtsp_mangle_tran(ctinfo, exp, prtspexp, pskb, lineoff, linelen)) + { + DEBUGP("hdr: Transport mangle failed"); + break; + } + get_skb_tcpdata(*pskb, &ptcp, &tcplen); + hdrslen -= (oldtcplen-tcplen); + //off -= (oldtcplen-tcplen); + //lineoff -= (oldtcplen-tcplen); + linelen -= (oldtcplen-tcplen); + DEBUGP("rep: len=%u, %.*s", linelen, (int)linelen, ptcp+lineoff); + } + } + + return NF_ACCEPT; +} + +static unsigned int +help(struct sk_buff **pskb, + enum ip_conntrack_info ctinfo, + unsigned int matchoff, + unsigned int matchlen, + struct ip_ct_rtsp_expect *ct_rtsp_info, + struct ip_conntrack_expect* exp) +{ + //struct iphdr* iph = (struct iphdr*)(*pskb)->nh.iph; + //struct tcphdr* tcph = (struct tcphdr*)((char*)iph + iph->ihl * 4); + //uint datalen; + + int dir = CTINFO2DIR(ctinfo); + int rc = NF_ACCEPT; + + DEBUGP("NAT rtsp help\n"); + + // Reply comes from server. + exp->saved_proto.udp.port = exp->tuple.dst.u.udp.port; + exp->dir = IP_CT_DIR_REPLY; + + // When you see the packet, we need to NAT it the same as the + // this one. + exp->expectfn = expected; + + switch (dir) + { + case IP_CT_DIR_ORIGINAL: + rc = help_out(pskb, ctinfo, matchoff, matchlen, ct_rtsp_info, exp ); + break; + case IP_CT_DIR_REPLY: + /* XXX: unmangle */ + DEBUGP("NAT rtsp help_in (unhandled)\n"); + rc = NF_ACCEPT; + break; + } + + return rc; +} + +static void __exit fini(void) +{ + ip_nat_rtsp_hook = NULL; + synchronize_net(); +} + +static int __init init(void) +{ + printk("ip_nat_rtsp v" IP_NF_RTSP_VERSION " loading\n"); + + BUG_ON(ip_nat_rtsp_hook); + ip_nat_rtsp_hook = help; + + 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); --- linux-2.6.19/net/ipv4/netfilter/Kconfig +++ linux-2.6.19/net/ipv4/netfilter/Kconfig @@ -656,4 +656,20 @@ Allows altering the ARP packet payload: source and destination hardware and network addresses. +config IP_NF_NAT_RTSP + tristate + depends on IP_NF_CONNTRACK!=n && IP_NF_NAT!=n + default IP_NF_NAT if IP_NF_RTSP=y + default m if IP_NF_RTSP=m + +config IP_NF_RTSP + tristate ' RTSP protocol support' + depends on IP_NF_CONNTRACK + help + Support the RTSP protocol. This allows UDP transports to be setup + properly, including RTP and RDT. + + If you want to compile it as a module, say 'M' here and read + Documentation/modules.txt. If unsure, say 'Y'. + endmenu --- linux-2.6.19/net/ipv4/netfilter/Makefile +++ linux-2.6.19/net/ipv4/netfilter/Makefile @@ -25,6 +25,11 @@ obj-$(CONFIG_IP_NF_CT_PROTO_SCTP) += ip_conntrack_proto_sctp.o # connection tracking helpers + +# rtsp protocol support +obj-$(CONFIG_IP_NF_RTSP) += ip_conntrack_rtsp.o +obj-$(CONFIG_IP_NF_NAT_RTSP) += ip_nat_rtsp.o + obj-$(CONFIG_IP_NF_H323) += ip_conntrack_h323.o obj-$(CONFIG_IP_NF_PPTP) += ip_conntrack_pptp.o obj-$(CONFIG_IP_NF_AMANDA) += ip_conntrack_amanda.o