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authorSridhar Samudrala <sri@us.ibm.com>2009-07-09 08:10:04 +0000
committerDavid S. Miller <davem@davemloft.net>2009-07-12 14:29:29 -0700
commitba73542585a4a3c8a708f502e62e6e63dd74b66c (patch)
tree5dbb997e5f2f0eeb1cbc03000f8121b322b254cd /net/ipv6/udp.c
parent7ea2f2c5a66e4e9a8d96296ac47ad895c467ee1d (diff)
udpv6: Handle large incoming UDP/IPv6 packets and support software UFO
- validate and forward GSO UDP/IPv6 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>
Diffstat (limited to 'net/ipv6/udp.c')
-rw-r--r--net/ipv6/udp.c93
1 files changed, 93 insertions, 0 deletions
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index f31b1b9b0e0..d79fa672445 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -1078,9 +1078,102 @@ int compat_udpv6_getsockopt(struct sock *sk, int level, int optname,
}
#endif
+static int udp6_ufo_send_check(struct sk_buff *skb)
+{
+ struct ipv6hdr *ipv6h;
+ struct udphdr *uh;
+
+ if (!pskb_may_pull(skb, sizeof(*uh)))
+ return -EINVAL;
+
+ ipv6h = ipv6_hdr(skb);
+ uh = udp_hdr(skb);
+
+ uh->check = ~csum_ipv6_magic(&ipv6h->saddr, &ipv6h->daddr, skb->len,
+ IPPROTO_UDP, 0);
+ skb->csum_start = skb_transport_header(skb) - skb->head;
+ skb->csum_offset = offsetof(struct udphdr, check);
+ skb->ip_summed = CHECKSUM_PARTIAL;
+ return 0;
+}
+
+static struct sk_buff *udp6_ufo_fragment(struct sk_buff *skb, int features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ unsigned int mss;
+ unsigned int unfrag_ip6hlen, unfrag_len;
+ struct frag_hdr *fptr;
+ u8 *mac_start, *prevhdr;
+ u8 nexthdr;
+ u8 frag_hdr_sz = sizeof(struct frag_hdr);
+ int offset;
+ __wsum csum;
+
+ mss = skb_shinfo(skb)->gso_size;
+ if (unlikely(skb->len <= mss))
+ goto out;
+
+ if (skb_gso_ok(skb, features | NETIF_F_GSO_ROBUST)) {
+ /* Packet is from an untrusted source, reset gso_segs. */
+ int type = skb_shinfo(skb)->gso_type;
+
+ if (unlikely(type & ~(SKB_GSO_UDP | SKB_GSO_DODGY) ||
+ !(type & (SKB_GSO_UDP))))
+ goto out;
+
+ skb_shinfo(skb)->gso_segs = DIV_ROUND_UP(skb->len, mss);
+
+ segs = NULL;
+ goto out;
+ }
+
+ /* Do software UFO. Complete and fill in the UDP checksum as HW cannot
+ * do checksum of UDP packets sent as multiple IP fragments.
+ */
+ offset = skb->csum_start - skb_headroom(skb);
+ csum = skb_checksum(skb, offset, skb->len- offset, 0);
+ offset += skb->csum_offset;
+ *(__sum16 *)(skb->data + offset) = csum_fold(csum);
+ skb->ip_summed = CHECKSUM_NONE;
+
+ /* Check if there is enough headroom to insert fragment header. */
+ if ((skb_headroom(skb) < frag_hdr_sz) &&
+ pskb_expand_head(skb, frag_hdr_sz, 0, GFP_ATOMIC))
+ goto out;
+
+ /* Find the unfragmentable header and shift it left by frag_hdr_sz
+ * bytes to insert fragment header.
+ */
+ unfrag_ip6hlen = ip6_find_1stfragopt(skb, &prevhdr);
+ nexthdr = *prevhdr;
+ *prevhdr = NEXTHDR_FRAGMENT;
+ unfrag_len = skb_network_header(skb) - skb_mac_header(skb) +
+ unfrag_ip6hlen;
+ mac_start = skb_mac_header(skb);
+ memmove(mac_start-frag_hdr_sz, mac_start, unfrag_len);
+
+ skb->mac_header -= frag_hdr_sz;
+ skb->network_header -= frag_hdr_sz;
+
+ fptr = (struct frag_hdr *)(skb_network_header(skb) + unfrag_ip6hlen);
+ fptr->nexthdr = nexthdr;
+ fptr->reserved = 0;
+ ipv6_select_ident(fptr);
+
+ /* Fragment the skb. ipv6 header and the remaining fields of the
+ * fragment header are updated in ipv6_gso_segment()
+ */
+ segs = skb_segment(skb, features);
+
+out:
+ return segs;
+}
+
static struct inet6_protocol udpv6_protocol = {
.handler = udpv6_rcv,
.err_handler = udpv6_err,
+ .gso_send_check = udp6_ufo_send_check,
+ .gso_segment = udp6_ufo_fragment,
.flags = INET6_PROTO_NOPOLICY|INET6_PROTO_FINAL,
};