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authorAnanda Raju <ananda.raju@neterion.com>2005-10-18 18:46:41 -0400
committerArnaldo Carvalho de Melo <acme@mandriva.com>2005-10-28 14:30:00 -0400
commite89e9cf539a28df7d0eb1d0a545368e9920b34ac (patch)
treeaae6a825f351ce931fcd30f1a865ebe65227c4b8 /include/linux/skbuff.h
parentde5144164f6242ccfa8c9b64eec570564f5eaf14 (diff)
[IPv4/IPv6]: UFO Scatter-gather approach
Attached is kernel patch for UDP Fragmentation Offload (UFO) feature. 1. This patch incorporate the review comments by Jeff Garzik. 2. Renamed USO as UFO (UDP Fragmentation Offload) 3. udp sendfile support with UFO This patches uses scatter-gather feature of skb to generate large UDP datagram. Below is a "how-to" on changes required in network device driver to use the UFO interface. UDP Fragmentation Offload (UFO) Interface: ------------------------------------------- UFO is a feature wherein the Linux kernel network stack will offload the IP fragmentation functionality of large UDP datagram to hardware. This will reduce the overhead of stack in fragmenting the large UDP datagram to MTU sized packets 1) Drivers indicate their capability of UFO using dev->features |= NETIF_F_UFO | NETIF_F_HW_CSUM | NETIF_F_SG NETIF_F_HW_CSUM is required for UFO over ipv6. 2) UFO packet will be submitted for transmission using driver xmit routine. UFO packet will have a non-zero value for "skb_shinfo(skb)->ufo_size" skb_shinfo(skb)->ufo_size will indicate the length of data part in each IP fragment going out of the adapter after IP fragmentation by hardware. skb->data will contain MAC/IP/UDP header and skb_shinfo(skb)->frags[] contains the data payload. The skb->ip_summed will be set to CHECKSUM_HW indicating that hardware has to do checksum calculation. Hardware should compute the UDP checksum of complete datagram and also ip header checksum of each fragmented IP packet. For IPV6 the UFO provides the fragment identification-id in skb_shinfo(skb)->ip6_frag_id. The adapter should use this ID for generating IPv6 fragments. Signed-off-by: Ananda Raju <ananda.raju@neterion.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (forwarded) Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Diffstat (limited to 'include/linux/skbuff.h')
-rw-r--r--include/linux/skbuff.h7
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index b756935da9c8..4286d832166f 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -137,6 +137,8 @@ struct skb_shared_info {
137 unsigned int nr_frags; 137 unsigned int nr_frags;
138 unsigned short tso_size; 138 unsigned short tso_size;
139 unsigned short tso_segs; 139 unsigned short tso_segs;
140 unsigned short ufo_size;
141 unsigned int ip6_frag_id;
140 struct sk_buff *frag_list; 142 struct sk_buff *frag_list;
141 skb_frag_t frags[MAX_SKB_FRAGS]; 143 skb_frag_t frags[MAX_SKB_FRAGS];
142}; 144};
@@ -341,6 +343,11 @@ extern void skb_over_panic(struct sk_buff *skb, int len,
341extern void skb_under_panic(struct sk_buff *skb, int len, 343extern void skb_under_panic(struct sk_buff *skb, int len,
342 void *here); 344 void *here);
343 345
346extern int skb_append_datato_frags(struct sock *sk, struct sk_buff *skb,
347 int getfrag(void *from, char *to, int offset,
348 int len,int odd, struct sk_buff *skb),
349 void *from, int length);
350
344struct skb_seq_state 351struct skb_seq_state
345{ 352{
346 __u32 lower_offset; 353 __u32 lower_offset;