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Date: Wed, 24 Jun 2009 09:16:50 -0700
From: Sridhar Samudrala <sri@...ibm.com>
To: Herbert Xu <herbert@...dor.apana.org.au>,
David Miller <davem@...emloft.net>,
netdev <netdev@...r.kernel.org>
Subject: [RFC 1/2] udpv4: Support software UFO and handle large incoming
UDP/IPv4 packets
[RFC 1/2] udpv4: Support software UFO and handle large incoming UDP/IPv4 packets
- validate and forward GSO UDP/IPv4 packets from untrusted sources(guests under KVM).
- do software UFO if the outgoing device doesn't support UFO.
Signed-off-by: Sridhar Samudrala <sri@...ibm.com>
diff --git a/include/net/udp.h b/include/net/udp.h
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -207,4 +207,7 @@ extern void udp4_proc_exit(void);
#endif
extern void udp_init(void);
+
+extern int udp4_ufo_send_check(struct sk_buff *skb);
+extern struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features);
#endif /* _UDP_H */
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
--- 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,
};
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1815,6 +1815,57 @@ void __init udp_init(void)
sysctl_udp_wmem_min = SK_MEM_QUANTUM;
}
+int udp4_ufo_send_check(struct sk_buff *skb)
+{
+ const struct iphdr *iph;
+ struct udphdr *uh;
+
+ if (!pskb_may_pull(skb, sizeof(*uh)))
+ return -EINVAL;
+
+ iph = ip_hdr(skb);
+ uh = udp_hdr(skb);
+
+ uh->check = 0;
+ uh->check = ~csum_tcpudp_magic(iph->saddr, iph->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;
+}
+
+struct sk_buff *udp4_ufo_fragment(struct sk_buff *skb, int features)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ unsigned int mss;
+
+ 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. IP headers of the fragments are updated in
+ * inet_gso_segment()
+ */
+ segs = skb_segment(skb, features);
+out:
+ return segs;
+}
+
EXPORT_SYMBOL(udp_disconnect);
EXPORT_SYMBOL(udp_ioctl);
EXPORT_SYMBOL(udp_prot);
--
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