netfilter: nf_nat: add protoff argument to packet mangling functions

For mangling IPv6 packets the protocol header offset needs to be known
by the NAT packet mangling functions. Add a so far unused protoff argument
and convert the conntrack and NAT helpers to use it in preparation of
IPv6 NAT.

Signed-off-by: Patrick McHardy <kaber@trash.net>

8 files changed, 100 insertions, 74 deletions

diff --git a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
index e7ff2dcab6ce..4ada3295d9a7 100644
--- a/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
+++ b/net/ipv4/netfilter/nf_conntrack_l3proto_ipv4.c
@@ -31,7 +31,8 @@
 
 int (*nf_nat_seq_adjust_hook)(struct sk_buff *skb,
 			      struct nf_conn *ct,
-			      enum ip_conntrack_info ctinfo);
+			      enum ip_conntrack_info ctinfo,
+			      unsigned int protoff);
 EXPORT_SYMBOL_GPL(nf_nat_seq_adjust_hook);
 
 static bool ipv4_pkt_to_tuple(const struct sk_buff *skb, unsigned int nhoff,
@@ -149,7 +150,8 @@ static unsigned int ipv4_confirm(unsigned int hooknum,
 		typeof(nf_nat_seq_adjust_hook) seq_adjust;
 
 		seq_adjust = rcu_dereference(nf_nat_seq_adjust_hook);
-		if (!seq_adjust || !seq_adjust(skb, ct, ctinfo)) {
+		if (!seq_adjust ||
+		    !seq_adjust(skb, ct, ctinfo, ip_hdrlen(skb))) {
 			NF_CT_STAT_INC_ATOMIC(nf_ct_net(ct), drop);
 			return NF_DROP;
 		}
diff --git a/net/ipv4/netfilter/nf_nat_amanda.c b/net/ipv4/netfilter/nf_nat_amanda.c
index 3c04d24e2976..75464b62f5f2 100644
--- a/net/ipv4/netfilter/nf_nat_amanda.c
+++ b/net/ipv4/netfilter/nf_nat_amanda.c
@@ -26,6 +26,7 @@ MODULE_ALIAS("ip_nat_amanda");
 
 static unsigned int help(struct sk_buff *skb,
 			 enum ip_conntrack_info ctinfo,
+			 unsigned int protoff,
 			 unsigned int matchoff,
 			 unsigned int matchlen,
 			 struct nf_conntrack_expect *exp)
@@ -61,7 +62,7 @@ static unsigned int help(struct sk_buff *skb,
 
 	sprintf(buffer, "%u", port);
 	ret = nf_nat_mangle_udp_packet(skb, exp->master, ctinfo,
-				       matchoff, matchlen,
+				       protoff, matchoff, matchlen,
 				       buffer, strlen(buffer));
 	if (ret != NF_ACCEPT)
 		nf_ct_unexpect_related(exp);
diff --git a/net/ipv4/netfilter/nf_nat_ftp.c b/net/ipv4/netfilter/nf_nat_ftp.c
index e462a957d080..5589f3af4a8e 100644
--- a/net/ipv4/netfilter/nf_nat_ftp.c
+++ b/net/ipv4/netfilter/nf_nat_ftp.c
@@ -55,6 +55,7 @@ static int nf_nat_ftp_fmt_cmd(enum nf_ct_ftp_type type,
 static unsigned int nf_nat_ftp(struct sk_buff *skb,
 			       enum ip_conntrack_info ctinfo,
 			       enum nf_ct_ftp_type type,
+			       unsigned int protoff,
 			       unsigned int matchoff,
 			       unsigned int matchlen,
 			       struct nf_conntrack_expect *exp)
@@ -100,7 +101,7 @@ static unsigned int nf_nat_ftp(struct sk_buff *skb,
 
 	pr_debug("calling nf_nat_mangle_tcp_packet\n");
 
-	if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, matchoff,
+	if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff, matchoff,
 				      matchlen, buffer, buflen))
 		goto out;
 
diff --git a/net/ipv4/netfilter/nf_nat_h323.c b/net/ipv4/netfilter/nf_nat_h323.c
index c6784a18c1c4..d2c228db38b5 100644
--- a/net/ipv4/netfilter/nf_nat_h323.c
+++ b/net/ipv4/netfilter/nf_nat_h323.c
@@ -21,7 +21,7 @@
 #include <linux/netfilter/nf_conntrack_h323.h>
 
 /****************************************************************************/
-static int set_addr(struct sk_buff *skb,
+static int set_addr(struct sk_buff *skb, unsigned int protoff,
 		    unsigned char **data, int dataoff,
 		    unsigned int addroff, __be32 ip, __be16 port)
 {
@@ -40,7 +40,7 @@ static int set_addr(struct sk_buff *skb,
 
 	if (ip_hdr(skb)->protocol == IPPROTO_TCP) {
 		if (!nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
-					      addroff, sizeof(buf),
+					      protoff, addroff, sizeof(buf),
 					      (char *) &buf, sizeof(buf))) {
 			net_notice_ratelimited("nf_nat_h323: nf_nat_mangle_tcp_packet error\n");
 			return -1;
@@ -54,7 +54,7 @@ static int set_addr(struct sk_buff *skb,
 		*data = skb->data + ip_hdrlen(skb) + th->doff * 4 + dataoff;
 	} else {
 		if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo,
-					      addroff, sizeof(buf),
+					      protoff, addroff, sizeof(buf),
 					      (char *) &buf, sizeof(buf))) {
 			net_notice_ratelimited("nf_nat_h323: nf_nat_mangle_udp_packet error\n");
 			return -1;
@@ -69,22 +69,22 @@ static int set_addr(struct sk_buff *skb,
 }
 
 /****************************************************************************/
-static int set_h225_addr(struct sk_buff *skb,
+static int set_h225_addr(struct sk_buff *skb, unsigned int protoff,
 			 unsigned char **data, int dataoff,
 			 TransportAddress *taddr,
 			 union nf_inet_addr *addr, __be16 port)
 {
-	return set_addr(skb, data, dataoff, taddr->ipAddress.ip,
+	return set_addr(skb, protoff, data, dataoff, taddr->ipAddress.ip,
 			addr->ip, port);
 }
 
 /****************************************************************************/
-static int set_h245_addr(struct sk_buff *skb,
+static int set_h245_addr(struct sk_buff *skb, unsigned protoff,
 			 unsigned char **data, int dataoff,
 			 H245_TransportAddress *taddr,
 			 union nf_inet_addr *addr, __be16 port)
 {
-	return set_addr(skb, data, dataoff,
+	return set_addr(skb, protoff, data, dataoff,
 			taddr->unicastAddress.iPAddress.network,
 			addr->ip, port);
 }
@@ -92,7 +92,7 @@ static int set_h245_addr(struct sk_buff *skb,
 /****************************************************************************/
 static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
 			enum ip_conntrack_info ctinfo,
-			unsigned char **data,
+			unsigned int protoff, unsigned char **data,
 			TransportAddress *taddr, int count)
 {
 	const struct nf_ct_h323_master *info = nfct_help_data(ct);
@@ -118,7 +118,8 @@ static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
 					 &addr.ip, port,
 					 &ct->tuplehash[!dir].tuple.dst.u3.ip,
 					 info->sig_port[!dir]);
-				return set_h225_addr(skb, data, 0, &taddr[i],
+				return set_h225_addr(skb, protoff, data, 0,
+						     &taddr[i],
 						     &ct->tuplehash[!dir].
 						     tuple.dst.u3,
 						     info->sig_port[!dir]);
@@ -129,7 +130,8 @@ static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
 					 &addr.ip, port,
 					 &ct->tuplehash[!dir].tuple.src.u3.ip,
 					 info->sig_port[!dir]);
-				return set_h225_addr(skb, data, 0, &taddr[i],
+				return set_h225_addr(skb, protoff, data, 0,
+						     &taddr[i],
 						     &ct->tuplehash[!dir].
 						     tuple.src.u3,
 						     info->sig_port[!dir]);
@@ -143,7 +145,7 @@ static int set_sig_addr(struct sk_buff *skb, struct nf_conn *ct,
 /****************************************************************************/
 static int set_ras_addr(struct sk_buff *skb, struct nf_conn *ct,
 			enum ip_conntrack_info ctinfo,
-			unsigned char **data,
+			unsigned int protoff, unsigned char **data,
 			TransportAddress *taddr, int count)
 {
 	int dir = CTINFO2DIR(ctinfo);
@@ -159,7 +161,7 @@ static int set_ras_addr(struct sk_buff *skb, struct nf_conn *ct,
 				 &addr.ip, ntohs(port),
 				 &ct->tuplehash[!dir].tuple.dst.u3.ip,
 				 ntohs(ct->tuplehash[!dir].tuple.dst.u.udp.port));
-			return set_h225_addr(skb, data, 0, &taddr[i],
+			return set_h225_addr(skb, protoff, data, 0, &taddr[i],
 					     &ct->tuplehash[!dir].tuple.dst.u3,
 					     ct->tuplehash[!dir].tuple.
 								dst.u.udp.port);
@@ -172,7 +174,7 @@ static int set_ras_addr(struct sk_buff *skb, struct nf_conn *ct,
 /****************************************************************************/
 static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
 			enum ip_conntrack_info ctinfo,
-			unsigned char **data, int dataoff,
+			unsigned int protoff, unsigned char **data, int dataoff,
 			H245_TransportAddress *taddr,
 			__be16 port, __be16 rtp_port,
 			struct nf_conntrack_expect *rtp_exp,
@@ -244,7 +246,7 @@ static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
 	}
 
 	/* Modify signal */
-	if (set_h245_addr(skb, data, dataoff, taddr,
+	if (set_h245_addr(skb, protoff, data, dataoff, taddr,
 			  &ct->tuplehash[!dir].tuple.dst.u3,
 			  htons((port & htons(1)) ? nated_port + 1 :
 						    nated_port)) == 0) {
@@ -275,7 +277,7 @@ static int nat_rtp_rtcp(struct sk_buff *skb, struct nf_conn *ct,
 /****************************************************************************/
 static int nat_t120(struct sk_buff *skb, struct nf_conn *ct,
 		    enum ip_conntrack_info ctinfo,
-		    unsigned char **data, int dataoff,
+		    unsigned int protoff, unsigned char **data, int dataoff,
 		    H245_TransportAddress *taddr, __be16 port,
 		    struct nf_conntrack_expect *exp)
 {
@@ -307,7 +309,7 @@ static int nat_t120(struct sk_buff *skb, struct nf_conn *ct,
 	}
 
 	/* Modify signal */
-	if (set_h245_addr(skb, data, dataoff, taddr,
+	if (set_h245_addr(skb, protoff, data, dataoff, taddr,
 			  &ct->tuplehash[!dir].tuple.dst.u3,
 			  htons(nated_port)) < 0) {
 		nf_ct_unexpect_related(exp);
@@ -326,7 +328,7 @@ static int nat_t120(struct sk_buff *skb, struct nf_conn *ct,
 /****************************************************************************/
 static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
 		    enum ip_conntrack_info ctinfo,
-		    unsigned char **data, int dataoff,
+		    unsigned int protoff, unsigned char **data, int dataoff,
 		    TransportAddress *taddr, __be16 port,
 		    struct nf_conntrack_expect *exp)
 {
@@ -363,7 +365,7 @@ static int nat_h245(struct sk_buff *skb, struct nf_conn *ct,
 	}
 
 	/* Modify signal */
-	if (set_h225_addr(skb, data, dataoff, taddr,
+	if (set_h225_addr(skb, protoff, data, dataoff, taddr,
 			  &ct->tuplehash[!dir].tuple.dst.u3,
 			  htons(nated_port)) == 0) {
 		/* Save ports */
@@ -416,7 +418,8 @@ static void ip_nat_q931_expect(struct nf_conn *new,
 /****************************************************************************/
 static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
 		    enum ip_conntrack_info ctinfo,
-		    unsigned char **data, TransportAddress *taddr, int idx,
+		    unsigned int protoff, unsigned char **data,
+		    TransportAddress *taddr, int idx,
 		    __be16 port, struct nf_conntrack_expect *exp)
 {
 	struct nf_ct_h323_master *info = nfct_help_data(ct);
@@ -453,7 +456,7 @@ static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
 	}
 
 	/* Modify signal */
-	if (set_h225_addr(skb, data, 0, &taddr[idx],
+	if (set_h225_addr(skb, protoff, data, 0, &taddr[idx],
 			  &ct->tuplehash[!dir].tuple.dst.u3,
 			  htons(nated_port)) == 0) {
 		/* Save ports */
@@ -464,7 +467,7 @@ static int nat_q931(struct sk_buff *skb, struct nf_conn *ct,
 		if (idx > 0 &&
 		    get_h225_addr(ct, *data, &taddr[0], &addr, &port) &&
 		    (ntohl(addr.ip) & 0xff000000) == 0x7f000000) {
-			set_h225_addr(skb, data, 0, &taddr[0],
+			set_h225_addr(skb, protoff, data, 0, &taddr[0],
 				      &ct->tuplehash[!dir].tuple.dst.u3,
 				      info->sig_port[!dir]);
 		}
@@ -507,6 +510,7 @@ static void ip_nat_callforwarding_expect(struct nf_conn *new,
 /****************************************************************************/
 static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct,
 			      enum ip_conntrack_info ctinfo,
+			      unsigned int protoff,
 			      unsigned char **data, int dataoff,
 			      TransportAddress *taddr, __be16 port,
 			      struct nf_conntrack_expect *exp)
@@ -541,7 +545,7 @@ static int nat_callforwarding(struct sk_buff *skb, struct nf_conn *ct,
 	}
 
 	/* Modify signal */
-	if (!set_h225_addr(skb, data, dataoff, taddr,
+	if (!set_h225_addr(skb, protoff, data, dataoff, taddr,
 			   &ct->tuplehash[!dir].tuple.dst.u3,
 			   htons(nated_port)) == 0) {
 		nf_ct_unexpect_related(exp);
diff --git a/net/ipv4/netfilter/nf_nat_helper.c b/net/ipv4/netfilter/nf_nat_helper.c
index 2e59ad0b90ca..2fefec5e757c 100644
--- a/net/ipv4/netfilter/nf_nat_helper.c
+++ b/net/ipv4/netfilter/nf_nat_helper.c
@@ -206,6 +206,7 @@ static void nf_nat_csum(struct sk_buff *skb, const struct iphdr *iph, void *data
 int __nf_nat_mangle_tcp_packet(struct sk_buff *skb,
 			       struct nf_conn *ct,
 			       enum ip_conntrack_info ctinfo,
+			       unsigned int protoff,
 			       unsigned int match_offset,
 			       unsigned int match_len,
 			       const char *rep_buffer,
@@ -257,6 +258,7 @@ int
 nf_nat_mangle_udp_packet(struct sk_buff *skb,
 			 struct nf_conn *ct,
 			 enum ip_conntrack_info ctinfo,
+			 unsigned int protoff,
 			 unsigned int match_offset,
 			 unsigned int match_len,
 			 const char *rep_buffer,
@@ -387,7 +389,8 @@ nf_nat_sack_adjust(struct sk_buff *skb,
 int
 nf_nat_seq_adjust(struct sk_buff *skb,
 		  struct nf_conn *ct,
-		  enum ip_conntrack_info ctinfo)
+		  enum ip_conntrack_info ctinfo,
+		  unsigned int protoff)
 {
 	struct tcphdr *tcph;
 	int dir;
@@ -401,10 +404,10 @@ nf_nat_seq_adjust(struct sk_buff *skb,
 	this_way = &nat->seq[dir];
 	other_way = &nat->seq[!dir];
 
-	if (!skb_make_writable(skb, ip_hdrlen(skb) + sizeof(*tcph)))
+	if (!skb_make_writable(skb, protoff + sizeof(*tcph)))
 		return 0;
 
-	tcph = (void *)skb->data + ip_hdrlen(skb);
+	tcph = (void *)skb->data + protoff;
 	if (after(ntohl(tcph->seq), this_way->correction_pos))
 		seqoff = this_way->offset_after;
 	else
diff --git a/net/ipv4/netfilter/nf_nat_irc.c b/net/ipv4/netfilter/nf_nat_irc.c
index 979ae165f4ef..5b0c20a1f08d 100644
--- a/net/ipv4/netfilter/nf_nat_irc.c
+++ b/net/ipv4/netfilter/nf_nat_irc.c
@@ -29,6 +29,7 @@ MODULE_ALIAS("ip_nat_irc");
 
 static unsigned int help(struct sk_buff *skb,
 			 enum ip_conntrack_info ctinfo,
+			 unsigned int protoff,
 			 unsigned int matchoff,
 			 unsigned int matchlen,
 			 struct nf_conntrack_expect *exp)
@@ -66,7 +67,7 @@ static unsigned int help(struct sk_buff *skb,
 		 buffer, &ip, port);
 
 	ret = nf_nat_mangle_tcp_packet(skb, exp->master, ctinfo,
-				       matchoff, matchlen, buffer,
+				       protoff, matchoff, matchlen, buffer,
 				       strlen(buffer));
 	if (ret != NF_ACCEPT)
 		nf_ct_unexpect_related(exp);
diff --git a/net/ipv4/netfilter/nf_nat_pptp.c b/net/ipv4/netfilter/nf_nat_pptp.c
index 388140881ebe..31ef890d894b 100644
--- a/net/ipv4/netfilter/nf_nat_pptp.c
+++ b/net/ipv4/netfilter/nf_nat_pptp.c
@@ -113,6 +113,7 @@ static int
 pptp_outbound_pkt(struct sk_buff *skb,
 		  struct nf_conn *ct,
 		  enum ip_conntrack_info ctinfo,
+		  unsigned int protoff,
 		  struct PptpControlHeader *ctlh,
 		  union pptp_ctrl_union *pptpReq)
 
@@ -175,7 +176,7 @@ pptp_outbound_pkt(struct sk_buff *skb,
 		 ntohs(REQ_CID(pptpReq, cid_off)), ntohs(new_callid));
 
 	/* mangle packet */
-	if (nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
+	if (nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff,
 				     cid_off + sizeof(struct pptp_pkt_hdr) +
 				     sizeof(struct PptpControlHeader),
 				     sizeof(new_callid), (char *)&new_callid,
@@ -216,6 +217,7 @@ static int
 pptp_inbound_pkt(struct sk_buff *skb,
 		 struct nf_conn *ct,
 		 enum ip_conntrack_info ctinfo,
+		 unsigned int protoff,
 		 struct PptpControlHeader *ctlh,
 		 union pptp_ctrl_union *pptpReq)
 {
@@ -268,7 +270,7 @@ pptp_inbound_pkt(struct sk_buff *skb,
 	pr_debug("altering peer call id from 0x%04x to 0x%04x\n",
 		 ntohs(REQ_CID(pptpReq, pcid_off)), ntohs(new_pcid));
 
-	if (nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
+	if (nf_nat_mangle_tcp_packet(skb, ct, ctinfo, protoff,
 				     pcid_off + sizeof(struct pptp_pkt_hdr) +
 				     sizeof(struct PptpControlHeader),
 				     sizeof(new_pcid), (char *)&new_pcid,
diff --git a/net/ipv4/netfilter/nf_nat_sip.c b/net/ipv4/netfilter/nf_nat_sip.c
index 4ad9cf173992..df626af8413c 100644
--- a/net/ipv4/netfilter/nf_nat_sip.c
+++ b/net/ipv4/netfilter/nf_nat_sip.c
@@ -30,7 +30,8 @@ MODULE_DESCRIPTION("SIP NAT helper");
 MODULE_ALIAS("ip_nat_sip");
 
 
-static unsigned int mangle_packet(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int mangle_packet(struct sk_buff *skb, unsigned int protoff,
+				  unsigned int dataoff,
 				  const char **dptr, unsigned int *datalen,
 				  unsigned int matchoff, unsigned int matchlen,
 				  const char *buffer, unsigned int buflen)
@@ -46,7 +47,7 @@ static unsigned int mangle_packet(struct sk_buff *skb, unsigned int dataoff,
 		matchoff += dataoff - baseoff;
 
 		if (!__nf_nat_mangle_tcp_packet(skb, ct, ctinfo,
-						matchoff, matchlen,
+						protoff, matchoff, matchlen,
 						buffer, buflen, false))
 			return 0;
 	} else {
@@ -54,7 +55,7 @@ static unsigned int mangle_packet(struct sk_buff *skb, unsigned int dataoff,
 		matchoff += dataoff - baseoff;
 
 		if (!nf_nat_mangle_udp_packet(skb, ct, ctinfo,
-					      matchoff, matchlen,
+					      protoff, matchoff, matchlen,
 					      buffer, buflen))
 			return 0;
 	}
@@ -65,7 +66,8 @@ static unsigned int mangle_packet(struct sk_buff *skb, unsigned int dataoff,
 	return 1;
 }
 
-static int map_addr(struct sk_buff *skb, unsigned int dataoff,
+static int map_addr(struct sk_buff *skb, unsigned int protoff,
+		    unsigned int dataoff,
 		    const char **dptr, unsigned int *datalen,
 		    unsigned int matchoff, unsigned int matchlen,
 		    union nf_inet_addr *addr, __be16 port)
@@ -94,11 +96,12 @@ static int map_addr(struct sk_buff *skb, unsigned int dataoff,
 
 	buflen = sprintf(buffer, "%pI4:%u", &newaddr, ntohs(newport));
 
-	return mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			     buffer, buflen);
+	return mangle_packet(skb, protoff, dataoff, dptr, datalen,
+			     matchoff, matchlen, buffer, buflen);
 }
 
-static int map_sip_addr(struct sk_buff *skb, unsigned int dataoff,
+static int map_sip_addr(struct sk_buff *skb, unsigned int protoff,
+			unsigned int dataoff,
 			const char **dptr, unsigned int *datalen,
 			enum sip_header_types type)
 {
@@ -111,11 +114,12 @@ static int map_sip_addr(struct sk_buff *skb, unsigned int dataoff,
 	if (ct_sip_parse_header_uri(ct, *dptr, NULL, *datalen, type, NULL,
 				    &matchoff, &matchlen, &addr, &port) <= 0)
 		return 1;
-	return map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			&addr, port);
+	return map_addr(skb, protoff, dataoff, dptr, datalen,
+			matchoff, matchlen, &addr, port);
 }
 
-static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int protoff,
+			       unsigned int dataoff,
 			       const char **dptr, unsigned int *datalen)
 {
 	enum ip_conntrack_info ctinfo;
@@ -132,8 +136,8 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
 		if (ct_sip_parse_request(ct, *dptr, *datalen,
 					 &matchoff, &matchlen,
 					 &addr, &port) > 0 &&
-		    !map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			      &addr, port))
+		    !map_addr(skb, protoff, dataoff, dptr, datalen,
+			      matchoff, matchlen, &addr, port))
 			return NF_DROP;
 		request = 1;
 	} else
@@ -164,8 +168,8 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
 		}
 
 		olen = *datalen;
-		if (!map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			      &addr, port))
+		if (!map_addr(skb, protoff, dataoff, dptr, datalen,
+			      matchoff, matchlen, &addr, port))
 			return NF_DROP;
 
 		matchend = matchoff + matchlen + *datalen - olen;
@@ -179,7 +183,7 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
 		    addr.ip != ct->tuplehash[!dir].tuple.dst.u3.ip) {
 			buflen = sprintf(buffer, "%pI4",
 					&ct->tuplehash[!dir].tuple.dst.u3.ip);
-			if (!mangle_packet(skb, dataoff, dptr, datalen,
+			if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
 					   poff, plen, buffer, buflen))
 				return NF_DROP;
 		}
@@ -193,7 +197,7 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
 		    addr.ip != ct->tuplehash[!dir].tuple.src.u3.ip) {
 			buflen = sprintf(buffer, "%pI4",
 					&ct->tuplehash[!dir].tuple.src.u3.ip);
-			if (!mangle_packet(skb, dataoff, dptr, datalen,
+			if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
 					   poff, plen, buffer, buflen))
 				return NF_DROP;
 		}
@@ -207,7 +211,7 @@ static unsigned int ip_nat_sip(struct sk_buff *skb, unsigned int dataoff,
 		    htons(n) != ct->tuplehash[!dir].tuple.src.u.udp.port) {
 			__be16 p = ct->tuplehash[!dir].tuple.src.u.udp.port;
 			buflen = sprintf(buffer, "%u", ntohs(p));
-			if (!mangle_packet(skb, dataoff, dptr, datalen,
+			if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
 					   poff, plen, buffer, buflen))
 				return NF_DROP;
 		}
@@ -221,13 +225,14 @@ next:
 				       SIP_HDR_CONTACT, &in_header,
 				       &matchoff, &matchlen,
 				       &addr, &port) > 0) {
-		if (!map_addr(skb, dataoff, dptr, datalen, matchoff, matchlen,
+		if (!map_addr(skb, protoff, dataoff, dptr, datalen,
+			      matchoff, matchlen,
 			      &addr, port))
 			return NF_DROP;
 	}
 
-	if (!map_sip_addr(skb, dataoff, dptr, datalen, SIP_HDR_FROM) ||
-	    !map_sip_addr(skb, dataoff, dptr, datalen, SIP_HDR_TO))
+	if (!map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_FROM) ||
+	    !map_sip_addr(skb, protoff, dataoff, dptr, datalen, SIP_HDR_TO))
 		return NF_DROP;
 
 	return NF_ACCEPT;
@@ -272,7 +277,8 @@ static void ip_nat_sip_expected(struct nf_conn *ct,
 	}
 }
 
-static unsigned int ip_nat_sip_expect(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int ip_nat_sip_expect(struct sk_buff *skb, unsigned int protoff,
+				      unsigned int dataoff,
 				      const char **dptr, unsigned int *datalen,
 				      struct nf_conntrack_expect *exp,
 				      unsigned int matchoff,
@@ -326,7 +332,7 @@ static unsigned int ip_nat_sip_expect(struct sk_buff *skb, unsigned int dataoff,
 	if (exp->tuple.dst.u3.ip != exp->saved_ip ||
 	    exp->tuple.dst.u.udp.port != exp->saved_proto.udp.port) {
 		buflen = sprintf(buffer, "%pI4:%u", &newip, port);
-		if (!mangle_packet(skb, dataoff, dptr, datalen,
+		if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
 				   matchoff, matchlen, buffer, buflen))
 			goto err;
 	}
@@ -337,7 +343,8 @@ err:
 	return NF_DROP;
 }
 
-static int mangle_content_len(struct sk_buff *skb, unsigned int dataoff,
+static int mangle_content_len(struct sk_buff *skb, unsigned int protoff,
+			      unsigned int dataoff,
 			      const char **dptr, unsigned int *datalen)
 {
 	enum ip_conntrack_info ctinfo;
@@ -359,11 +366,12 @@ static int mangle_content_len(struct sk_buff *skb, unsigned int dataoff,
 		return 0;
 
 	buflen = sprintf(buffer, "%u", c_len);
-	return mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			     buffer, buflen);
+	return mangle_packet(skb, protoff, dataoff, dptr, datalen,
+			     matchoff, matchlen, buffer, buflen);
 }
 
-static int mangle_sdp_packet(struct sk_buff *skb, unsigned int dataoff,
+static int mangle_sdp_packet(struct sk_buff *skb, unsigned int protoff,
+			     unsigned int dataoff,
 			     const char **dptr, unsigned int *datalen,
 			     unsigned int sdpoff,
 			     enum sdp_header_types type,
@@ -377,11 +385,12 @@ static int mangle_sdp_packet(struct sk_buff *skb, unsigned int dataoff,
 	if (ct_sip_get_sdp_header(ct, *dptr, sdpoff, *datalen, type, term,
 				  &matchoff, &matchlen) <= 0)
 		return -ENOENT;
-	return mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			     buffer, buflen) ? 0 : -EINVAL;
+	return mangle_packet(skb, protoff, dataoff, dptr, datalen,
+			     matchoff, matchlen, buffer, buflen) ? 0 : -EINVAL;
 }
 
-static unsigned int ip_nat_sdp_addr(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int ip_nat_sdp_addr(struct sk_buff *skb, unsigned int protoff,
+				    unsigned int dataoff,
 				    const char **dptr, unsigned int *datalen,
 				    unsigned int sdpoff,
 				    enum sdp_header_types type,
@@ -392,14 +401,15 @@ static unsigned int ip_nat_sdp_addr(struct sk_buff *skb, unsigned int dataoff,
 	unsigned int buflen;
 
 	buflen = sprintf(buffer, "%pI4", &addr->ip);
-	if (mangle_sdp_packet(skb, dataoff, dptr, datalen, sdpoff, type, term,
-			      buffer, buflen))
+	if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen,
+			      sdpoff, type, term, buffer, buflen))
 		return 0;
 
-	return mangle_content_len(skb, dataoff, dptr, datalen);
+	return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
 }
 
-static unsigned int ip_nat_sdp_port(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int ip_nat_sdp_port(struct sk_buff *skb, unsigned int protoff,
+				    unsigned int dataoff,
 				    const char **dptr, unsigned int *datalen,
 				    unsigned int matchoff,
 				    unsigned int matchlen,
@@ -409,14 +419,15 @@ static unsigned int ip_nat_sdp_port(struct sk_buff *skb, unsigned int dataoff,
 	unsigned int buflen;
 
 	buflen = sprintf(buffer, "%u", port);
-	if (!mangle_packet(skb, dataoff, dptr, datalen, matchoff, matchlen,
-			   buffer, buflen))
+	if (!mangle_packet(skb, protoff, dataoff, dptr, datalen,
+			   matchoff, matchlen, buffer, buflen))
 		return 0;
 
-	return mangle_content_len(skb, dataoff, dptr, datalen);
+	return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
 }
 
-static unsigned int ip_nat_sdp_session(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int ip_nat_sdp_session(struct sk_buff *skb, unsigned int protoff,
+				       unsigned int dataoff,
 				       const char **dptr, unsigned int *datalen,
 				       unsigned int sdpoff,
 				       const union nf_inet_addr *addr)
@@ -426,12 +437,12 @@ static unsigned int ip_nat_sdp_session(struct sk_buff *skb, unsigned int dataoff
 
 	/* Mangle session description owner and contact addresses */
 	buflen = sprintf(buffer, "%pI4", &addr->ip);
-	if (mangle_sdp_packet(skb, dataoff, dptr, datalen, sdpoff,
+	if (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff,
 			       SDP_HDR_OWNER_IP4, SDP_HDR_MEDIA,
 			       buffer, buflen))
 		return 0;
 
-	switch (mangle_sdp_packet(skb, dataoff, dptr, datalen, sdpoff,
+	switch (mangle_sdp_packet(skb, protoff, dataoff, dptr, datalen, sdpoff,
 				  SDP_HDR_CONNECTION_IP4, SDP_HDR_MEDIA,
 				  buffer, buflen)) {
 	case 0:
@@ -448,12 +459,13 @@ static unsigned int ip_nat_sdp_session(struct sk_buff *skb, unsigned int dataoff
 		return 0;
 	}
 
-	return mangle_content_len(skb, dataoff, dptr, datalen);
+	return mangle_content_len(skb, protoff, dataoff, dptr, datalen);
 }
 
 /* So, this packet has hit the connection tracking matching code.
    Mangle it, and change the expectation to match the new version. */
-static unsigned int ip_nat_sdp_media(struct sk_buff *skb, unsigned int dataoff,
+static unsigned int ip_nat_sdp_media(struct sk_buff *skb, unsigned int protoff,
+				     unsigned int dataoff,
 				     const char **dptr, unsigned int *datalen,
 				     struct nf_conntrack_expect *rtp_exp,
 				     struct nf_conntrack_expect *rtcp_exp,
@@ -514,7 +526,7 @@ static unsigned int ip_nat_sdp_media(struct sk_buff *skb, unsigned int dataoff,
 
 	/* Update media port. */
 	if (rtp_exp->tuple.dst.u.udp.port != rtp_exp->saved_proto.udp.port &&
-	    !ip_nat_sdp_port(skb, dataoff, dptr, datalen,
+	    !ip_nat_sdp_port(skb, protoff, dataoff, dptr, datalen,
 			     mediaoff, medialen, port))
 		goto err2;