Rebase files to rsdk 3.2 and refresh patches. Compilable (not by humans).

Signed-off-by: Roman Yeryomin <roman@advem.lv>

1 files changed, 497 insertions, 0 deletions

diff --git a/target/linux/realtek/files/net/ipv4/netfilter/nf_nat_rtsp.c b/target/linux/realtek/files/net/ipv4/netfilter/nf_nat_rtsp.c
new file mode 100644
index 000000000..6423661fe
--- /dev/null
+++ b/target/linux/realtek/files/net/ipv4/netfilter/nf_nat_rtsp.c
@@ -0,0 +1,497 @@
+/*
+ * RTSP extension for TCP NAT alteration
+ * (C) 2003 by Tom Marshall <tmarshall at real.com>
+ * 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 <net/tcp.h>
+#include <net/netfilter/nf_nat_helper.h>
+#include <net/netfilter/nf_nat_rule.h>
+#include <net/netfilter/nf_conntrack_expect.h>
+#include <linux/netfilter/nf_conntrack_rtsp.h>
+
+#include <linux/inet.h>
+#include <linux/ctype.h>
+#define NF_NEED_STRNCASECMP
+#define NF_NEED_STRTOU16
+#include <linux/netfilter_helpers.h>
+#define NF_NEED_MIME_NEXTLINE
+#include <linux/netfilter_mime.h>
+
+#define INFOP(fmt, args...) printk(KERN_INFO "%s: %s: " fmt, __FILE__, __FUNCTION__ , ## args)
+#define IP_NF_RTSP_DEBUG
+#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 char*    stunaddr = NULL;
+static char*    destaction = NULL;
+
+static u_int32_t extip = 0;
+static int       dstact = 0;
+
+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;
+}
+
+/*** 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,
+                 struct nf_conntrack_expect* 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) */
+    u_int32_t   newip;
+    u_int16_t   loport, hiport;
+    uint        off = 0;
+    uint        diff;           /* Number of bytes we removed */
+
+    struct nf_conn *ct = exp->master;
+    struct nf_conntrack_tuple *t;
+
+    char    szextaddr[15+1];
+    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);
+
+    newip = ct->tuplehash[IP_CT_DIR_REPLY].tuple.dst.u3.ip;
+    t = &exp->tuple;
+    t->dst.u3.ip = newip;
+
+    extaddrlen = extip ? sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(extip))
+                       : sprintf(szextaddr, "%u.%u.%u.%u", NIPQUAD(newip));
+    pr_debug("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 (nf_ct_expect_related(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? */
+        {
+            t->dst.u.udp.port = htons(loport);
+            if (nf_ct_expect_related(exp) == 0)
+            {
+                hiport = loport + 1; //~exp->mask.dst.u.udp.port;
+                pr_debug("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 (nf_ct_expect_related(exp) == 0)
+            {
+                pr_debug("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 (nf_ct_expect_related(exp) == 0)
+            {
+                pr_debug("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 (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
+                                                         off, diff, NULL, 0))
+                    {
+                        /* mangle failed, all we can do is bail */
+						nf_ct_unexpect_related(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 (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
+                                              origoff, origlen, rbuf, rbuflen))
+                    {
+                        /* mangle failed, all we can do is bail */
+						nf_ct_unexpect_related(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,
+	 unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp, 
+	 struct nf_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(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 (!rtsp_mangle_tran(ctinfo, exp, prtspexp, skb, lineoff, linelen))
+            {
+				pr_debug("hdr: Transport mangle failed");
+                break;
+            }
+            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
+help(struct sk_buff *skb, enum ip_conntrack_info ctinfo, 
+     unsigned int matchoff, unsigned int matchlen, struct ip_ct_rtsp_expect* prtspexp,
+     struct nf_conntrack_expect* exp)
+{
+    int dir = CTINFO2DIR(ctinfo);
+    int rc = NF_ACCEPT;
+
+    switch (dir)
+    {
+    case IP_CT_DIR_ORIGINAL:
+        rc = help_out(skb, ctinfo, matchoff, matchlen, prtspexp, exp);
+        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 expected(struct nf_conn* ct, struct nf_conntrack_expect *exp)
+{
+    struct nf_nat_multi_range_compat mr;
+    u_int32_t newdstip, newsrcip, newip;
+
+    struct nf_conn *master = ct->master;
+
+    newdstip = master->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
+    newsrcip = ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple.src.u3.ip;
+    //FIXME (how to port that ?)
+    //code from 2.4 : newip = (HOOK2MANIP(hooknum) == IP_NAT_MANIP_SRC) ? newsrcip : newdstip;
+    newip = newdstip;
+
+    pr_debug("newsrcip=%u.%u.%u.%u, newdstip=%u.%u.%u.%u, newip=%u.%u.%u.%u\n",
+           NIPQUAD(newsrcip), NIPQUAD(newdstip), NIPQUAD(newip));
+
+    mr.rangesize = 1;
+    // We don't want to manip the per-protocol, just the IPs. 
+    mr.range[0].flags = IP_NAT_RANGE_MAP_IPS;
+    mr.range[0].min_ip = mr.range[0].max_ip = newip;
+
+    nf_nat_setup_info(ct, &mr.range[0], IP_NAT_MANIP_DST);
+}
+
+
+static void __exit fini(void)
+{
+	nf_nat_rtsp_hook = NULL;
+        nf_nat_rtsp_hook_expectfn = 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);
+	nf_nat_rtsp_hook = help;
+    nf_nat_rtsp_hook_expectfn = &expected;
+
+	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);