[NET]: Add software TSOv4
This patch adds the GSO implementation for IPv4 TCP.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 062dd1a..0e029c4 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -258,6 +258,7 @@
#include <linux/random.h>
#include <linux/bootmem.h>
#include <linux/cache.h>
+#include <linux/err.h>
#include <net/icmp.h>
#include <net/tcp.h>
@@ -2144,6 +2145,67 @@
EXPORT_SYMBOL(compat_tcp_getsockopt);
#endif
+struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int sg)
+{
+ struct sk_buff *segs = ERR_PTR(-EINVAL);
+ struct tcphdr *th;
+ unsigned thlen;
+ unsigned int seq;
+ unsigned int delta;
+ unsigned int oldlen;
+ unsigned int len;
+
+ if (!pskb_may_pull(skb, sizeof(*th)))
+ goto out;
+
+ th = skb->h.th;
+ thlen = th->doff * 4;
+ if (thlen < sizeof(*th))
+ goto out;
+
+ if (!pskb_may_pull(skb, thlen))
+ goto out;
+
+ oldlen = ~htonl(skb->len);
+ __skb_pull(skb, thlen);
+
+ segs = skb_segment(skb, sg);
+ if (IS_ERR(segs))
+ goto out;
+
+ len = skb_shinfo(skb)->gso_size;
+ delta = csum_add(oldlen, htonl(thlen + len));
+
+ skb = segs;
+ th = skb->h.th;
+ seq = ntohl(th->seq);
+
+ do {
+ th->fin = th->psh = 0;
+
+ if (skb->ip_summed == CHECKSUM_NONE) {
+ th->check = csum_fold(csum_partial(
+ skb->h.raw, thlen, csum_add(skb->csum, delta)));
+ }
+
+ seq += len;
+ skb = skb->next;
+ th = skb->h.th;
+
+ th->seq = htonl(seq);
+ th->cwr = 0;
+ } while (skb->next);
+
+ if (skb->ip_summed == CHECKSUM_NONE) {
+ delta = csum_add(oldlen, htonl(skb->tail - skb->h.raw));
+ th->check = csum_fold(csum_partial(
+ skb->h.raw, thlen, csum_add(skb->csum, delta)));
+ }
+
+out:
+ return segs;
+}
+
extern void __skb_cb_too_small_for_tcp(int, int);
extern struct tcp_congestion_ops tcp_reno;