[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/include/linux/skbuff.h b/include/linux/skbuff.h
index 97b0d2d..a45bba9 100644 (file)
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -1297,6 +1297,7 @@ extern void              skb_split(struct sk_buff *skb,
                                 struct sk_buff *skb1, const u32 len);
 
 extern void           skb_release_data(struct sk_buff *skb);
+extern struct sk_buff *skb_segment(struct sk_buff *skb, int sg);
 
 static inline void *skb_header_pointer(const struct sk_buff *skb, int offset,
                                       int len, void *buffer)

diff --git a/include/net/protocol.h b/include/net/protocol.h
index bcaee39..3b6dc15 100644 (file)
--- a/include/net/protocol.h
+++ b/include/net/protocol.h
@@ -36,6 +36,7 @@
 struct net_protocol {
        int                     (*handler)(struct sk_buff *skb);
        void                    (*err_handler)(struct sk_buff *skb, u32 info);
+       struct sk_buff         *(*gso_segment)(struct sk_buff *skb, int sg);
        int                     no_policy;
 };
 

diff --git a/include/net/tcp.h b/include/net/tcp.h
index b197a9e..ca3d38d 100644 (file)
--- a/include/net/tcp.h
+++ b/include/net/tcp.h
@@ -1086,6 +1086,8 @@ extern struct request_sock_ops tcp_request_sock_ops;
 
 extern int tcp_v4_destroy_sock(struct sock *sk);
 
+extern struct sk_buff *tcp_tso_segment(struct sk_buff *skb, int sg);
+
 #ifdef CONFIG_PROC_FS
 extern int  tcp4_proc_init(void);
 extern void tcp4_proc_exit(void);

diff --git a/net/core/skbuff.c b/net/core/skbuff.c
index 368d985..8e5044b 100644 (file)
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -1842,6 +1842,132 @@ unsigned char *skb_pull_rcsum(struct sk_buff *skb, unsigned int len)
 
 EXPORT_SYMBOL_GPL(skb_pull_rcsum);
 
+/**
+ *     skb_segment - Perform protocol segmentation on skb.
+ *     @skb: buffer to segment
+ *     @sg: whether scatter-gather can be used for generated segments
+ *
+ *     This function performs segmentation on the given skb.  It returns
+ *     the segment at the given position.  It returns NULL if there are
+ *     no more segments to generate, or when an error is encountered.
+ */
+struct sk_buff *skb_segment(struct sk_buff *skb, int sg)
+{
+       struct sk_buff *segs = NULL;
+       struct sk_buff *tail = NULL;
+       unsigned int mss = skb_shinfo(skb)->gso_size;
+       unsigned int doffset = skb->data - skb->mac.raw;
+       unsigned int offset = doffset;
+       unsigned int headroom;
+       unsigned int len;
+       int nfrags = skb_shinfo(skb)->nr_frags;
+       int err = -ENOMEM;
+       int i = 0;
+       int pos;
+
+       __skb_push(skb, doffset);
+       headroom = skb_headroom(skb);
+       pos = skb_headlen(skb);
+
+       do {
+               struct sk_buff *nskb;
+               skb_frag_t *frag;
+               int hsize, nsize;
+               int k;
+               int size;
+
+               len = skb->len - offset;
+               if (len > mss)
+                       len = mss;
+
+               hsize = skb_headlen(skb) - offset;
+               if (hsize < 0)
+                       hsize = 0;
+               nsize = hsize + doffset;
+               if (nsize > len + doffset || !sg)
+                       nsize = len + doffset;
+
+               nskb = alloc_skb(nsize + headroom, GFP_ATOMIC);
+               if (unlikely(!nskb))
+                       goto err;
+
+               if (segs)
+                       tail->next = nskb;
+               else
+                       segs = nskb;
+               tail = nskb;
+
+               nskb->dev = skb->dev;
+               nskb->priority = skb->priority;
+               nskb->protocol = skb->protocol;
+               nskb->dst = dst_clone(skb->dst);
+               memcpy(nskb->cb, skb->cb, sizeof(skb->cb));
+               nskb->pkt_type = skb->pkt_type;
+               nskb->mac_len = skb->mac_len;
+
+               skb_reserve(nskb, headroom);
+               nskb->mac.raw = nskb->data;
+               nskb->nh.raw = nskb->data + skb->mac_len;
+               nskb->h.raw = nskb->nh.raw + (skb->h.raw - skb->nh.raw);
+               memcpy(skb_put(nskb, doffset), skb->data, doffset);
+
+               if (!sg) {
+                       nskb->csum = skb_copy_and_csum_bits(skb, offset,
+                                                           skb_put(nskb, len),
+                                                           len, 0);
+                       continue;
+               }
+
+               frag = skb_shinfo(nskb)->frags;
+               k = 0;
+
+               nskb->ip_summed = CHECKSUM_HW;
+               nskb->csum = skb->csum;
+               memcpy(skb_put(nskb, hsize), skb->data + offset, hsize);
+
+               while (pos < offset + len) {
+                       BUG_ON(i >= nfrags);
+
+                       *frag = skb_shinfo(skb)->frags[i];
+                       get_page(frag->page);
+                       size = frag->size;
+
+                       if (pos < offset) {
+                               frag->page_offset += offset - pos;
+                               frag->size -= offset - pos;
+                       }
+
+                       k++;
+
+                       if (pos + size <= offset + len) {
+                               i++;
+                               pos += size;
+                       } else {
+                               frag->size -= pos + size - (offset + len);
+                               break;
+                       }
+
+                       frag++;
+               }
+
+               skb_shinfo(nskb)->nr_frags = k;
+               nskb->data_len = len - hsize;
+               nskb->len += nskb->data_len;
+               nskb->truesize += nskb->data_len;
+       } while ((offset += len) < skb->len);
+
+       return segs;
+
+err:
+       while ((skb = segs)) {
+               segs = skb->next;
+               kfree(skb);
+       }
+       return ERR_PTR(err);
+}
+
+EXPORT_SYMBOL_GPL(skb_segment);
+
 void __init skb_init(void)
 {
        skbuff_head_cache = kmem_cache_create("skbuff_head_cache",

diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
index 0a27745..461216b 100644 (file)
--- a/net/ipv4/af_inet.c
+++ b/net/ipv4/af_inet.c
@@ -68,6 +68,7 @@
  */
 
 #include <linux/config.h>
+#include <linux/err.h>
 #include <linux/errno.h>
 #include <linux/types.h>
 #include <linux/socket.h>
@@ -1096,6 +1097,54 @@ int inet_sk_rebuild_header(struct sock *sk)
 
 EXPORT_SYMBOL(inet_sk_rebuild_header);
 
+static struct sk_buff *inet_gso_segment(struct sk_buff *skb, int sg)
+{
+       struct sk_buff *segs = ERR_PTR(-EINVAL);
+       struct iphdr *iph;
+       struct net_protocol *ops;
+       int proto;
+       int ihl;
+       int id;
+
+       if (!pskb_may_pull(skb, sizeof(*iph)))
+               goto out;
+
+       iph = skb->nh.iph;
+       ihl = iph->ihl * 4;
+       if (ihl < sizeof(*iph))
+               goto out;
+
+       if (!pskb_may_pull(skb, ihl))
+               goto out;
+
+       skb->h.raw = __skb_pull(skb, ihl);
+       iph = skb->nh.iph;
+       id = ntohs(iph->id);
+       proto = iph->protocol & (MAX_INET_PROTOS - 1);
+       segs = ERR_PTR(-EPROTONOSUPPORT);
+
+       rcu_read_lock();
+       ops = rcu_dereference(inet_protos[proto]);
+       if (ops && ops->gso_segment)
+               segs = ops->gso_segment(skb, sg);
+       rcu_read_unlock();
+
+       if (IS_ERR(segs))
+               goto out;
+
+       skb = segs;
+       do {
+               iph = skb->nh.iph;
+               iph->id = htons(id++);
+               iph->tot_len = htons(skb->len - skb->mac_len);
+               iph->check = 0;
+               iph->check = ip_fast_csum(skb->nh.raw, iph->ihl);
+       } while ((skb = skb->next));
+
+out:
+       return segs;
+}
+
 #ifdef CONFIG_IP_MULTICAST
 static struct net_protocol igmp_protocol = {
        .handler =      igmp_rcv,
@@ -1105,6 +1154,7 @@ static struct net_protocol igmp_protocol = {
 static struct net_protocol tcp_protocol = {
        .handler =      tcp_v4_rcv,
        .err_handler =  tcp_v4_err,
+       .gso_segment =  tcp_tso_segment,
        .no_policy =    1,
 };
 
@@ -1150,6 +1200,7 @@ static int ipv4_proc_init(void);
 static struct packet_type ip_packet_type = {
        .type = __constant_htons(ETH_P_IP),
        .func = ip_rcv,
+       .gso_segment = inet_gso_segment,
 };
 
 static int __init inet_init(void)

diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 062dd1a..0e029c4 100644 (file)
--- 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 @@ int compat_tcp_getsockopt(struct sock *sk, int level, int optname,
 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;