[IPV6]: Allow to replace skbuff by TLV parser.

In receiving Mobile IPv6 home address option which is a TLV carried by
destination options header, kernel will try to mangle source adderss
of packet. Think of cloned skbuff it is required to replace it by the
parser just like routing header case.

This is a framework to achieve that to allow TLV parser to replace
inbound skbuff pointer.

Signed-off-by: Masahide NAKAMURA <nakam@linux-ipv6.org>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/net/ipv6.h b/include/net/ipv6.h
index c4ea1271057601471d513e6b96d25873b4e737b2..8e6ec6063f8ce1a00197744c135e1e3a7b65107c 100644 (file)
--- a/include/net/ipv6.h
+++ b/include/net/ipv6.h
@@ -229,7 +229,7 @@ extern int                  ip6_ra_control(struct sock *sk, int sel,
                                               void (*destructor)(struct sock *));
 
 
-extern int                     ipv6_parse_hopopts(struct sk_buff *skb);
+extern int                     ipv6_parse_hopopts(struct sk_buff **skbp);
 
 extern struct ipv6_txoptions *  ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt);
 extern struct ipv6_txoptions * ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 50ff49e518bcd846613731c7482c96657bac51bd..1cdd0f0b5d34d28ed68bf32a4e2c3012c3852605 100644 (file)
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -102,7 +102,7 @@ int ipv6_find_tlv(struct sk_buff *skb, int offset, int type)
 
 struct tlvtype_proc {
        int     type;
-       int     (*func)(struct sk_buff *skb, int offset);
+       int     (*func)(struct sk_buff **skbp, int offset);
 };
 
 /*********************
@@ -111,8 +111,10 @@ struct tlvtype_proc {
 
 /* An unknown option is detected, decide what to do */
 
-static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
+static int ip6_tlvopt_unknown(struct sk_buff **skbp, int optoff)
 {
+       struct sk_buff *skb = *skbp;
+
        switch ((skb->nh.raw[optoff] & 0xC0) >> 6) {
        case 0: /* ignore */
                return 1;
@@ -137,8 +139,9 @@ static int ip6_tlvopt_unknown(struct sk_buff *skb, int optoff)
 
 /* Parse tlv encoded option header (hop-by-hop or destination) */
 
-static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
+static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff **skbp)
 {
+       struct sk_buff *skb = *skbp;
        struct tlvtype_proc *curr;
        int off = skb->h.raw - skb->nh.raw;
        int len = ((skb->h.raw[1]+1)<<3);
@@ -168,13 +171,13 @@ static int ip6_parse_tlv(struct tlvtype_proc *procs, struct sk_buff *skb)
                                        /* type specific length/alignment 
                                           checks will be performed in the 
                                           func(). */
-                                       if (curr->func(skb, off) == 0)
+                                       if (curr->func(skbp, off) == 0)
                                                return 0;
                                        break;
                                }
                        }
                        if (curr->type < 0) {
-                               if (ip6_tlvopt_unknown(skb, off) == 0)
+                               if (ip6_tlvopt_unknown(skbp, off) == 0)
                                        return 0;
                        }
                        break;
@@ -213,7 +216,8 @@ static int ipv6_destopt_rcv(struct sk_buff **skbp)
        opt->lastopt = skb->h.raw - skb->nh.raw;
        opt->dst1 = skb->h.raw - skb->nh.raw;
 
-       if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
+       if (ip6_parse_tlv(tlvprocdestopt_lst, skbp)) {
+               skb = *skbp;
                skb->h.raw += ((skb->h.raw[1]+1)<<3);
                opt->nhoff = opt->dst1;
                return 1;
@@ -517,8 +521,10 @@ EXPORT_SYMBOL_GPL(ipv6_invert_rthdr);
 
 /* Router Alert as of RFC 2711 */
 
-static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
+static int ipv6_hop_ra(struct sk_buff **skbp, int optoff)
 {
+       struct sk_buff *skb = *skbp;
+
        if (skb->nh.raw[optoff+1] == 2) {
                IP6CB(skb)->ra = optoff;
                return 1;
@@ -531,8 +537,9 @@ static int ipv6_hop_ra(struct sk_buff *skb, int optoff)
 
 /* Jumbo payload */
 
-static int ipv6_hop_jumbo(struct sk_buff *skb, int optoff)
+static int ipv6_hop_jumbo(struct sk_buff **skbp, int optoff)
 {
+       struct sk_buff *skb = *skbp;
        u32 pkt_len;
 
        if (skb->nh.raw[optoff+1] != 4 || (optoff&3) != 2) {
@@ -581,8 +588,9 @@ static struct tlvtype_proc tlvprochopopt_lst[] = {
        { -1, }
 };
 
-int ipv6_parse_hopopts(struct sk_buff *skb)
+int ipv6_parse_hopopts(struct sk_buff **skbp)
 {
+       struct sk_buff *skb = *skbp;
        struct inet6_skb_parm *opt = IP6CB(skb);
 
        /*
@@ -598,7 +606,8 @@ int ipv6_parse_hopopts(struct sk_buff *skb)
        }
 
        opt->hop = sizeof(struct ipv6hdr);
-       if (ip6_parse_tlv(tlvprochopopt_lst, skb)) {
+       if (ip6_parse_tlv(tlvprochopopt_lst, skbp)) {
+               skb = *skbp;
                skb->h.raw += (skb->h.raw[1]+1)<<3;
                opt->nhoff = sizeof(struct ipv6hdr);
                return 1;

diff --git a/net/ipv6/ip6_input.c b/net/ipv6/ip6_input.c
index 25c2a9e0389549f05578c2ad3155ab105ef8ecfa..6b8e6d76a58bf2633ea46c84bd7c392367065f42 100644 (file)
--- a/net/ipv6/ip6_input.c
+++ b/net/ipv6/ip6_input.c
@@ -111,7 +111,7 @@ int ipv6_rcv(struct sk_buff *skb, struct net_device *dev, struct packet_type *pt
        }
 
        if (hdr->nexthdr == NEXTHDR_HOP) {
-               if (ipv6_parse_hopopts(skb) < 0) {
+               if (ipv6_parse_hopopts(&skb) < 0) {
                        IP6_INC_STATS_BH(IPSTATS_MIB_INHDRERRORS);
                        return 0;
                }