udpv4: Handle large incoming UDP/IPv4 packets and support software UFO.

- validate and forward GSO UDP/IPv4 packets from untrusted sources.
- do software UFO if the outgoing device doesn't support UFO.

Signed-off-by: Sridhar Samudrala <sri@us.ibm.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 1 deletions

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 566ea6c4321d..197d024b2536 100644
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -1187,6 +1187,7 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
         int proto;
         int ihl;
         int id;
+        unsigned int offset = 0;
 
         if (!(features & NETIF_F_V4_CSUM))
                 features &= ~NETIF_F_SG;
@@ -1229,7 +1230,14 @@ static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int features)
         skb = segs;
         do {
                 iph = ip_hdr(skb);
-                iph->id = htons(id++);
+                if (proto == IPPROTO_UDP) {
+                        iph->id = htons(id);
+                        iph->frag_off = htons(offset >> 3);
+                        if (skb->next != NULL)
+                                iph->frag_off |= htons(IP_MF);
+                        offset += (skb->len - skb->mac_len - iph->ihl * 4);
+                } else
+                        iph->id = htons(id++);
                 iph->tot_len = htons(skb->len - skb->mac_len);
                 iph->check = 0;
                 iph->check = ip_fast_csum(skb_network_header(skb), iph->ihl);
@@ -1425,6 +1433,8 @@ static struct net_protocol tcp_protocol = {
 static struct net_protocol udp_protocol = {
         .handler =      udp_rcv,
         .err_handler =  udp_err,
+        .gso_send_check = udp4_ufo_send_check,
+        .gso_segment = udp4_ufo_fragment,
         .no_policy =    1,
         .netns_ok =     1,
 };