[IPV6]: Support several new sockopt / ancillary data in Advanced API (RFC3542).

Support several new socket options / ancillary data:
  IPV6_RECVPKTINFO, IPV6_PKTINFO,
  IPV6_RECVHOPOPTS, IPV6_HOPOPTS,
  IPV6_RECVDSTOPTS, IPV6_DSTOPTS, IPV6_RTHDRDSTOPTS,
  IPV6_RECVRTHDR, IPV6_RTHDR,
  IPV6_RECVHOPOPTS, IPV6_HOPOPTS

Old semantics are preserved as IPV6_2292xxxx so that
we can maintain backward compatibility.

Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>

1 files changed, 104 insertions, 3 deletions

diff --git a/net/ipv6/exthdrs.c b/net/ipv6/exthdrs.c
index 5be6da2584ee..ffcda45e2c1e 100644
--- a/net/ipv6/exthdrs.c
+++ b/net/ipv6/exthdrs.c
@@ -164,6 +164,7 @@ static int ipv6_destopt_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
                 return -1;
         }
 
+        opt->lastopt = skb->h.raw - skb->nh.raw;
         opt->dst1 = skb->h.raw - skb->nh.raw;
 
         if (ip6_parse_tlv(tlvprocdestopt_lst, skb)) {
@@ -243,6 +244,7 @@ static int ipv6_rthdr_rcv(struct sk_buff **skbp, unsigned int *nhoffp)
 
 looped_back:
         if (hdr->segments_left == 0) {
+                opt->lastopt = skb->h.raw - skb->nh.raw;
                 opt->srcrt = skb->h.raw - skb->nh.raw;
                 skb->h.raw += (hdr->hdrlen + 1) << 3;
                 opt->dst0 = opt->dst1;
@@ -539,10 +541,15 @@ void ipv6_push_nfrag_opts(struct sk_buff *skb, struct ipv6_txoptions *opt,
                           u8 *proto,
                           struct in6_addr **daddr)
 {
-        if (opt->srcrt)
+        if (opt->srcrt) {
                 ipv6_push_rthdr(skb, proto, opt->srcrt, daddr);
-        if (opt->dst0opt)
-                ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
+                /*
+                 * IPV6_RTHDRDSTOPTS is ignored
+                 * unless IPV6_RTHDR is set (RFC3542).
+                 */
+                if (opt->dst0opt)
+                        ipv6_push_exthdr(skb, proto, NEXTHDR_DEST, opt->dst0opt);
+        }
         if (opt->hopopt)
                 ipv6_push_exthdr(skb, proto, NEXTHDR_HOP, opt->hopopt);
 }
@@ -573,3 +580,97 @@ ipv6_dup_options(struct sock *sk, struct ipv6_txoptions *opt)
         }
         return opt2;
 }
+
+static int ipv6_renew_option(void *ohdr,
+                             struct ipv6_opt_hdr __user *newopt, int newoptlen,
+                             int inherit,
+                             struct ipv6_opt_hdr **hdr,
+                             char **p)
+{
+        if (inherit) {
+                if (ohdr) {
+                        memcpy(*p, ohdr, ipv6_optlen((struct ipv6_opt_hdr *)ohdr));
+                        *hdr = (struct ipv6_opt_hdr *)*p;
+                        *p += CMSG_ALIGN(ipv6_optlen(*(struct ipv6_opt_hdr **)hdr));
+                }
+        } else {
+                if (newopt) {
+                        if (copy_from_user(*p, newopt, newoptlen))
+                                return -EFAULT;
+                        *hdr = (struct ipv6_opt_hdr *)*p;
+                        if (ipv6_optlen(*(struct ipv6_opt_hdr **)hdr) > newoptlen)
+                                return -EINVAL;
+                        *p += CMSG_ALIGN(newoptlen);
+                }
+        }
+        return 0;
+}
+
+struct ipv6_txoptions *
+ipv6_renew_options(struct sock *sk, struct ipv6_txoptions *opt,
+                   int newtype,
+                   struct ipv6_opt_hdr __user *newopt, int newoptlen)
+{
+        int tot_len = 0;
+        char *p;
+        struct ipv6_txoptions *opt2;
+        int err;
+
+        if (newtype != IPV6_HOPOPTS && opt->hopopt)
+                tot_len += CMSG_ALIGN(ipv6_optlen(opt->hopopt));
+        if (newtype != IPV6_RTHDRDSTOPTS && opt->dst0opt)
+                tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst0opt));
+        if (newtype != IPV6_RTHDR && opt->srcrt)
+                tot_len += CMSG_ALIGN(ipv6_optlen(opt->srcrt));
+        if (newtype != IPV6_DSTOPTS && opt->dst1opt)
+                tot_len += CMSG_ALIGN(ipv6_optlen(opt->dst1opt));
+        if (newopt && newoptlen)
+                tot_len += CMSG_ALIGN(newoptlen);
+
+        if (!tot_len)
+                return NULL;
+
+        opt2 = sock_kmalloc(sk, tot_len, GFP_ATOMIC);
+        if (!opt2)
+                return ERR_PTR(-ENOBUFS);
+
+        memset(opt2, 0, tot_len);
+
+        opt2->tot_len = tot_len;
+        p = (char *)(opt2 + 1);
+
+        err = ipv6_renew_option(opt->hopopt, newopt, newoptlen,
+                                newtype != IPV6_HOPOPTS,
+                                &opt2->hopopt, &p);
+        if (err)
+                goto out;
+
+        err = ipv6_renew_option(opt->dst0opt, newopt, newoptlen,
+                                newtype != IPV6_RTHDRDSTOPTS,
+                                &opt2->dst0opt, &p);
+        if (err)
+                goto out;
+
+        err = ipv6_renew_option(opt->srcrt, newopt, newoptlen,
+                                newtype != IPV6_RTHDR,
+                                (struct ipv6_opt_hdr **)opt2->srcrt, &p);
+        if (err)
+                goto out;
+
+        err = ipv6_renew_option(opt->dst1opt, newopt, newoptlen,
+                                newtype != IPV6_DSTOPTS,
+                                &opt2->dst1opt, &p);
+        if (err)
+                goto out;
+
+        opt2->opt_nflen = (opt2->hopopt ? ipv6_optlen(opt2->hopopt) : 0) +
+                          (opt2->dst0opt ? ipv6_optlen(opt2->dst0opt) : 0) +
+                          (opt2->srcrt ? ipv6_optlen(opt2->srcrt) : 0);
+        opt2->opt_flen = (opt2->dst1opt ? ipv6_optlen(opt2->dst1opt) : 0);
+
+        return opt2;
+out:
+        sock_kfree_s(sk, p, tot_len);
+        return ERR_PTR(err);
+}
+