diff mbox

[RFC,1/2] udpv4: Support software UFO and handle large incoming UDP/IPv4 packets

Message ID 1245860210.23459.13.camel@w-sridhar.beaverton.ibm.com
State RFC, archived
Delegated to: David Miller
Headers show

Commit Message

Sridhar Samudrala June 24, 2009, 4:16 p.m. UTC 
[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@us.ibm.com>



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Comments

Herbert Xu June 25, 2009, 8:01 a.m. UTC | #1 
On Wed, Jun 24, 2009 at 09:16:50AM -0700, Sridhar Samudrala wrote:
> [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@us.ibm.com>

Looks good to me.

Thanks,
diff mbox

Patch

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);