ipv6: Clean up ipv6_select_ident() and ip6_fragment()

This patch changes the ipv6_select_ident() signature to return a
fragment id instead of taking a whole frag_hdr as a param to
only set the frag_hdr->identification.

It also cleans up ip6_fragment() to obtain the fragment id at the
beginning instead of using multiple "if" later to check fragment id
has been generated or not.

Signed-off-by: Martin KaFai Lau <kafai@fb.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Cc: Steffen Klassert <steffen.klassert@secunet.com>
Cc: Julian Anastasov <ja@ssi.bg>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 8 insertions, 14 deletions

diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c
index bc09cb97b840..05e2cdf938bd 100644
--- a/net/ipv6/ip6_output.c
+++ b/net/ipv6/ip6_output.c
@@ -551,7 +551,7 @@ int ip6_fragment(struct sock *sk, struct sk_buff *skb,
         struct frag_hdr *fh;
         unsigned int mtu, hlen, left, len;
         int hroom, troom;
-        __be32 frag_id = 0;
+        __be32 frag_id;
         int ptr, offset = 0, err = 0;
         u8 *prevhdr, nexthdr = 0;
         struct net *net = dev_net(skb_dst(skb)->dev);
@@ -584,6 +584,8 @@ int ip6_fragment(struct sock *sk, struct sk_buff *skb,
         }
         mtu -= hlen + sizeof(struct frag_hdr);
 
+        frag_id = ipv6_select_ident(net, rt);
+
         if (skb_has_frag_list(skb)) {
                 int first_len = skb_pagelen(skb);
                 struct sk_buff *frag2;
@@ -632,11 +634,10 @@ int ip6_fragment(struct sock *sk, struct sk_buff *skb,
                 skb_reset_network_header(skb);
                 memcpy(skb_network_header(skb), tmp_hdr, hlen);
 
-                ipv6_select_ident(net, fh, rt);
                 fh->nexthdr = nexthdr;
                 fh->reserved = 0;
                 fh->frag_off = htons(IP6_MF);
-                frag_id = fh->identification;
+                fh->identification = frag_id;
 
                 first_len = skb_pagelen(skb);
                 skb->data_len = first_len - skb_headlen(skb);
@@ -778,11 +779,7 @@ slow_path:
                  */
                 fh->nexthdr = nexthdr;
                 fh->reserved = 0;
-                if (!frag_id) {
-                        ipv6_select_ident(net, fh, rt);
-                        frag_id = fh->identification;
-                } else
-                        fh->identification = frag_id;
+                fh->identification = frag_id;
 
                 /*
                  *      Copy a block of the IP datagram.
@@ -1064,7 +1061,6 @@ static inline int ip6_ufo_append_data(struct sock *sk,
 
 {
         struct sk_buff *skb;
-        struct frag_hdr fhdr;
         int err;
 
         /* There is support for UDP large send offload by network
@@ -1106,8 +1102,7 @@ static inline int ip6_ufo_append_data(struct sock *sk,
         skb_shinfo(skb)->gso_size = (mtu - fragheaderlen -
                                      sizeof(struct frag_hdr)) & ~7;
         skb_shinfo(skb)->gso_type = SKB_GSO_UDP;
-        ipv6_select_ident(sock_net(sk), &fhdr, rt);
-        skb_shinfo(skb)->ip6_frag_id = fhdr.identification;
+        skb_shinfo(skb)->ip6_frag_id = ipv6_select_ident(sock_net(sk), rt);
 
 append:
         return skb_append_datato_frags(sk, skb, getfrag, from,
diff --git a/net/ipv6/output_core.c b/net/ipv6/output_core.c
index 85892af57364..ef0e2326496b 100644
--- a/net/ipv6/output_core.c
+++ b/net/ipv6/output_core.c
@@ -60,8 +60,7 @@ void ipv6_proxy_select_ident(struct net *net, struct sk_buff *skb)
 }
 EXPORT_SYMBOL_GPL(ipv6_proxy_select_ident);
 
-void ipv6_select_ident(struct net *net, struct frag_hdr *fhdr,
-                       struct rt6_info *rt)
+u32 ipv6_select_ident(struct net *net, struct rt6_info *rt)
 {
         static u32 ip6_idents_hashrnd __read_mostly;
         u32 id;
@@ -70,7 +69,7 @@ void ipv6_select_ident(struct net *net, struct frag_hdr *fhdr,
 
         id = __ipv6_select_ident(net, ip6_idents_hashrnd, &rt->rt6i_dst.addr,
                                  &rt->rt6i_src.addr);
-        fhdr->identification = htonl(id);
+        return htonl(id);
 }
 EXPORT_SYMBOL(ipv6_select_ident);