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Commit 624f8b7b authored by Patrick McHardy's avatar Patrick McHardy Committed by David S. Miller
Browse files

[NETFILTER]: nf_nat_sip: get rid of text based header translation 



Use the URI parsing helper to get the numerical addresses and get rid of the
text based header translation.

Signed-off-by: default avatarPatrick McHardy <kaber@trash.net>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 05e3ced2

include/linux/netfilter/nf_conntrack_sip.h

+2 −1
Original line number Diff line number Diff line
@@ -62,7 +62,8 @@ extern unsigned int (*nf_nat_sdp_hook)(struct sk_buff *skb, 


extern int ct_sip_parse_request(const struct nf_conn *ct,

				const char *dptr, unsigned int datalen,

				unsigned int *matchoff, unsigned int *matchlen);

				unsigned int *matchoff, unsigned int *matchlen,

				union nf_inet_addr *addr, __be16 *port);

extern int ct_sip_get_header(const struct nf_conn *ct, const char *dptr,

			     unsigned int dataoff, unsigned int datalen,

			     enum sip_header_types type,

net/ipv4/netfilter/nf_nat_sip.c

+38 −62
Original line number Diff line number Diff line
@@ -26,39 +26,6 @@ MODULE_AUTHOR("Christian Hentschel <chentschel@arnet.com.ar>"); 
MODULE_DESCRIPTION("SIP NAT helper");

MODULE_ALIAS("ip_nat_sip");



struct addr_map {

	struct {

		char		src[sizeof("nnn.nnn.nnn.nnn:nnnnn")];

		char		dst[sizeof("nnn.nnn.nnn.nnn:nnnnn")];

		unsigned int	srclen, srciplen;

		unsigned int	dstlen, dstiplen;

	} addr[IP_CT_DIR_MAX];

};



static void addr_map_init(const struct nf_conn *ct, struct addr_map *map)

{

	const struct nf_conntrack_tuple *t;

	enum ip_conntrack_dir dir;

	unsigned int n;



	for (dir = 0; dir < IP_CT_DIR_MAX; dir++) {

		t = &ct->tuplehash[dir].tuple;



		n = sprintf(map->addr[dir].src, "%u.%u.%u.%u",

			    NIPQUAD(t->src.u3.ip));

		map->addr[dir].srciplen = n;

		n += sprintf(map->addr[dir].src + n, ":%u",

			     ntohs(t->src.u.udp.port));

		map->addr[dir].srclen = n;



		n = sprintf(map->addr[dir].dst, "%u.%u.%u.%u",

			    NIPQUAD(t->dst.u3.ip));

		map->addr[dir].dstiplen = n;

		n += sprintf(map->addr[dir].dst + n, ":%u",

			     ntohs(t->dst.u.udp.port));

		map->addr[dir].dstlen = n;

	}

}



static unsigned int mangle_packet(struct sk_buff *skb,

				  const char **dptr, unsigned int *datalen,
@@ -81,43 +48,51 @@ static unsigned int mangle_packet(struct sk_buff *skb, 
static int map_addr(struct sk_buff *skb,

		    const char **dptr, unsigned int *datalen,

		    unsigned int matchoff, unsigned int matchlen,

		    struct addr_map *map)

		    union nf_inet_addr *addr, __be16 port)

{

	enum ip_conntrack_info ctinfo;

	struct nf_conn *ct __maybe_unused = nf_ct_get(skb, &ctinfo);

	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);

	enum ip_conntrack_dir dir = CTINFO2DIR(ctinfo);

	unsigned int addrlen;

	char *addr;



	if ((matchlen == map->addr[dir].srciplen ||

	     matchlen == map->addr[dir].srclen) &&

	    strncmp(*dptr + matchoff, map->addr[dir].src, matchlen) == 0) {

		addr    = map->addr[!dir].dst;

		addrlen = map->addr[!dir].dstlen;

	} else if ((matchlen == map->addr[dir].dstiplen ||

		    matchlen == map->addr[dir].dstlen) &&

		   strncmp(*dptr + matchoff, map->addr[dir].dst, matchlen) == 0) {

		addr    = map->addr[!dir].src;

		addrlen = map->addr[!dir].srclen;

	char buffer[sizeof("nnn.nnn.nnn.nnn:nnnnn")];

	unsigned int buflen;

	__be32 newaddr;

	__be16 newport;



	if (ct->tuplehash[dir].tuple.src.u3.ip == addr->ip &&

	    ct->tuplehash[dir].tuple.src.u.udp.port == port) {

		newaddr = ct->tuplehash[!dir].tuple.dst.u3.ip;

		newport = ct->tuplehash[!dir].tuple.dst.u.udp.port;

	} else if (ct->tuplehash[dir].tuple.dst.u3.ip == addr->ip &&

		   ct->tuplehash[dir].tuple.dst.u.udp.port == port) {

		newaddr = ct->tuplehash[!dir].tuple.src.u3.ip;

		newport = ct->tuplehash[!dir].tuple.src.u.udp.port;

	} else

		return 1;



	if (newaddr == addr->ip && newport == port)

		return 1;



	buflen = sprintf(buffer, "%u.%u.%u.%u:%u",

			 NIPQUAD(newaddr), ntohs(newport));



	return mangle_packet(skb, dptr, datalen, matchoff, matchlen,

			     addr, addrlen);

			     buffer, buflen);

}



static int map_sip_addr(struct sk_buff *skb,

			const char **dptr, unsigned int *datalen,

			enum sip_header_types type, struct addr_map *map)

			enum sip_header_types type)

{

	enum ip_conntrack_info ctinfo;

	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);

	unsigned int matchlen, matchoff;

	union nf_inet_addr addr;

	__be16 port;



	if (ct_sip_get_header(ct, *dptr, 0, *datalen, type,

			      &matchoff, &matchlen) <= 0)

	if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL,

				    &matchoff, &matchlen, &addr, &port) <= 0)

		return 1;

	return map_addr(skb, dptr, datalen, matchoff, matchlen, map);

	return map_addr(skb, dptr, datalen, matchoff, matchlen, &addr, port);

}



static unsigned int ip_nat_sip(struct sk_buff *skb,
@@ -125,26 +100,27 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, 
{

	enum ip_conntrack_info ctinfo;

	struct nf_conn *ct = nf_ct_get(skb, &ctinfo);

	struct addr_map map;

	unsigned int matchoff, matchlen;

	union nf_inet_addr addr;

	__be16 port;



	if (*datalen < strlen("SIP/2.0"))

		return NF_ACCEPT;



	addr_map_init(ct, &map);



	/* Basic rules: requests and responses. */

	if (strnicmp(*dptr, "SIP/2.0", strlen("SIP/2.0")) != 0) {

		if (ct_sip_parse_request(ct, *dptr, *datalen,

					 &matchoff, &matchlen) > 0 &&

		    !map_addr(skb, dptr, datalen, matchoff, matchlen, &map))

					 &matchoff, &matchlen,

					 &addr, &port) > 0 &&

		    !map_addr(skb, dptr, datalen, matchoff, matchlen,

			      &addr, port))

			return NF_DROP;

	}



	if (!map_sip_addr(skb, dptr, datalen, SIP_HDR_FROM, &map) ||

	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_TO, &map) ||

	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_VIA, &map) ||

	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_CONTACT, &map))

	if (!map_sip_addr(skb, dptr, datalen, SIP_HDR_FROM) ||

	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_TO) ||

	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_VIA) ||

	    !map_sip_addr(skb, dptr, datalen, SIP_HDR_CONTACT))

		return NF_DROP;

	return NF_ACCEPT;

}

net/netfilter/nf_conntrack_sip.c

+22 −5
Original line number Diff line number Diff line
@@ -151,10 +151,12 @@ static int skp_epaddr_len(const struct nf_conn *ct, const char *dptr, 
 */

int ct_sip_parse_request(const struct nf_conn *ct,

			 const char *dptr, unsigned int datalen,

			 unsigned int *matchoff, unsigned int *matchlen)

			 unsigned int *matchoff, unsigned int *matchlen,

			 union nf_inet_addr *addr, __be16 *port)

{

	const char *start = dptr, *limit = dptr + datalen;

	const char *start = dptr, *limit = dptr + datalen, *end;

	unsigned int mlen;

	unsigned int p;

	int shift = 0;



	/* Skip method and following whitespace */
@@ -173,10 +175,25 @@ int ct_sip_parse_request(const struct nf_conn *ct, 
		if (strnicmp(dptr, "sip:", strlen("sip:")) == 0)

			break;

	}

	*matchlen = skp_epaddr_len(ct, dptr, limit, &shift);

	if (!*matchlen)

	if (!skp_epaddr_len(ct, dptr, limit, &shift))

		return 0;

	*matchoff = dptr - start + shift;

	dptr += shift;



	if (!parse_addr(ct, dptr, &end, addr, limit))

		return -1;

	if (end < limit && *end == ':') {

		end++;

		p = simple_strtoul(end, (char **)&end, 10);

		if (p < 1024 || p > 65535)

			return -1;

		*port = htons(p);

	} else

		*port = htons(SIP_PORT);



	if (end == dptr)

		return 0;

	*matchoff = dptr - start;

	*matchlen = end - dptr;

	return 1;

}

EXPORT_SYMBOL_GPL(ct_sip_parse_request);