[NET]: Merge TSO/UFO fields in sk_buff

Having separate fields in sk_buff for TSO/UFO (tso_size/ufo_size) is not
going to scale if we add any more segmentation methods (e.g., DCCP).  So
let's merge them.

They were used to tell the protocol of a packet.  This function has been
subsumed by the new gso_type field.  This is essentially a set of netdev
feature bits (shifted by 16 bits) that are required to process a specific
skb.  As such it's easy to tell whether a given device can process a GSO
skb: you just have to and the gso_type field and the netdev's features
field.

I've made gso_type a conjunction.  The idea is that you have a base type
(e.g., SKB_GSO_TCPV4) that can be modified further to support new features.
For example, if we add a hardware TSO type that supports ECN, they would
declare NETIF_F_TSO | NETIF_F_TSO_ECN.  All TSO packets with CWR set would
have a gso_type of SKB_GSO_TCPV4 | SKB_GSO_TCPV4_ECN while all other TSO
packets would be SKB_GSO_TCPV4.  This means that only the CWR packets need
to be emulated in software.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

4 files changed, 40 insertions, 29 deletions

diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index 8538aac..7624fd1 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -210,8 +210,7 @@ static inline int ip_finish_output(struct sk_buff *skb)
 		return dst_output(skb);
 	}
 #endif
-	if (skb->len > dst_mtu(skb->dst) &&
-	    !(skb_shinfo(skb)->ufo_size || skb_shinfo(skb)->tso_size))
+	if (skb->len > dst_mtu(skb->dst) && !skb_shinfo(skb)->gso_size)
 		return ip_fragment(skb, ip_finish_output2);
 	else
 		return ip_finish_output2(skb);
@@ -362,7 +361,7 @@ packet_routed:
 	}
 
 	ip_select_ident_more(iph, &rt->u.dst, sk,
-			     (skb_shinfo(skb)->tso_segs ?: 1) - 1);
+			     (skb_shinfo(skb)->gso_segs ?: 1) - 1);
 
 	/* Add an IP checksum. */
 	ip_send_check(iph);
@@ -744,7 +743,8 @@ static inline int ip_ufo_append_data(struct sock *sk,
 			       (length - transhdrlen));
 	if (!err) {
 		/* specify the length of each IP datagram fragment*/
-		skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen);
+		skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
 		__skb_queue_tail(&sk->sk_write_queue, skb);
 
 		return 0;
@@ -1087,14 +1087,16 @@ ssize_t	ip_append_page(struct sock *sk, struct page *page,
 
 	inet->cork.length += size;
 	if ((sk->sk_protocol == IPPROTO_UDP) &&
-	    (rt->u.dst.dev->features & NETIF_F_UFO))
-		skb_shinfo(skb)->ufo_size = (mtu - fragheaderlen);
+	    (rt->u.dst.dev->features & NETIF_F_UFO)) {
+		skb_shinfo(skb)->gso_size = mtu - fragheaderlen;
+		skb_shinfo(skb)->gso_type = SKB_GSO_UDPV4;
+	}
 
 
 	while (size > 0) {
 		int i;
 
-		if (skb_shinfo(skb)->ufo_size)
+		if (skb_shinfo(skb)->gso_size)
 			len = size;
 		else {
 
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 74998f2..062dd1a 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -571,7 +571,7 @@ new_segment:
 		skb->ip_summed = CHECKSUM_HW;
 		tp->write_seq += copy;
 		TCP_SKB_CB(skb)->end_seq += copy;
-		skb_shinfo(skb)->tso_segs = 0;
+		skb_shinfo(skb)->gso_segs = 0;
 
 		if (!copied)
 			TCP_SKB_CB(skb)->flags &= ~TCPCB_FLAG_PSH;
@@ -818,7 +818,7 @@ new_segment:
 
 			tp->write_seq += copy;
 			TCP_SKB_CB(skb)->end_seq += copy;
-			skb_shinfo(skb)->tso_segs = 0;
+			skb_shinfo(skb)->gso_segs = 0;
 
 			from += copy;
 			copied += copy;
diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c
index e08245b..94fe5b1 100644
--- a/net/ipv4/tcp_input.c
+++ b/net/ipv4/tcp_input.c
@@ -1073,7 +1073,7 @@ tcp_sacktag_write_queue(struct sock *sk, struct sk_buff *ack_skb, u32 prior_snd_
 				else
 					pkt_len = (end_seq -
 						   TCP_SKB_CB(skb)->seq);
-				if (tcp_fragment(sk, skb, pkt_len, skb_shinfo(skb)->tso_size))
+				if (tcp_fragment(sk, skb, pkt_len, skb_shinfo(skb)->gso_size))
 					break;
 				pcount = tcp_skb_pcount(skb);
 			}
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index 07bb5a2..bdd71db 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -515,15 +515,17 @@ static void tcp_set_skb_tso_segs(struct sock *sk, struct sk_buff *skb, unsigned
 		/* Avoid the costly divide in the normal
 		 * non-TSO case.
 		 */
-		skb_shinfo(skb)->tso_segs = 1;
-		skb_shinfo(skb)->tso_size = 0;
+		skb_shinfo(skb)->gso_segs = 1;
+		skb_shinfo(skb)->gso_size = 0;
+		skb_shinfo(skb)->gso_type = 0;
 	} else {
 		unsigned int factor;
 
 		factor = skb->len + (mss_now - 1);
 		factor /= mss_now;
-		skb_shinfo(skb)->tso_segs = factor;
-		skb_shinfo(skb)->tso_size = mss_now;
+		skb_shinfo(skb)->gso_segs = factor;
+		skb_shinfo(skb)->gso_size = mss_now;
+		skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
 	}
 }
 
@@ -914,7 +916,7 @@ static int tcp_init_tso_segs(struct sock *sk, struct sk_buff *skb, unsigned int
 
 	if (!tso_segs ||
 	    (tso_segs > 1 &&
-	     skb_shinfo(skb)->tso_size != mss_now)) {
+	     tcp_skb_mss(skb) != mss_now)) {
 		tcp_set_skb_tso_segs(sk, skb, mss_now);
 		tso_segs = tcp_skb_pcount(skb);
 	}
@@ -1724,8 +1726,9 @@ int tcp_retransmit_skb(struct sock *sk, struct sk_buff *skb)
 	   tp->snd_una == (TCP_SKB_CB(skb)->end_seq - 1)) {
 		if (!pskb_trim(skb, 0)) {
 			TCP_SKB_CB(skb)->seq = TCP_SKB_CB(skb)->end_seq - 1;
-			skb_shinfo(skb)->tso_segs = 1;
-			skb_shinfo(skb)->tso_size = 0;
+			skb_shinfo(skb)->gso_segs = 1;
+			skb_shinfo(skb)->gso_size = 0;
+			skb_shinfo(skb)->gso_type = 0;
 			skb->ip_summed = CHECKSUM_NONE;
 			skb->csum = 0;
 		}
@@ -1930,8 +1933,9 @@ void tcp_send_fin(struct sock *sk)
 		skb->csum = 0;
 		TCP_SKB_CB(skb)->flags = (TCPCB_FLAG_ACK | TCPCB_FLAG_FIN);
 		TCP_SKB_CB(skb)->sacked = 0;
-		skb_shinfo(skb)->tso_segs = 1;
-		skb_shinfo(skb)->tso_size = 0;
+		skb_shinfo(skb)->gso_segs = 1;
+		skb_shinfo(skb)->gso_size = 0;
+		skb_shinfo(skb)->gso_type = 0;
 
 		/* FIN eats a sequence byte, write_seq advanced by tcp_queue_skb(). */
 		TCP_SKB_CB(skb)->seq = tp->write_seq;
@@ -1963,8 +1967,9 @@ void tcp_send_active_reset(struct sock *sk, gfp_t priority)
 	skb->csum = 0;
 	TCP_SKB_CB(skb)->flags = (TCPCB_FLAG_ACK | TCPCB_FLAG_RST);
 	TCP_SKB_CB(skb)->sacked = 0;
-	skb_shinfo(skb)->tso_segs = 1;
-	skb_shinfo(skb)->tso_size = 0;
+	skb_shinfo(skb)->gso_segs = 1;
+	skb_shinfo(skb)->gso_size = 0;
+	skb_shinfo(skb)->gso_type = 0;
 
 	/* Send it off. */
 	TCP_SKB_CB(skb)->seq = tcp_acceptable_seq(sk, tp);
@@ -2047,8 +2052,9 @@ struct sk_buff * tcp_make_synack(struct sock *sk, struct dst_entry *dst,
 	TCP_SKB_CB(skb)->seq = tcp_rsk(req)->snt_isn;
 	TCP_SKB_CB(skb)->end_seq = TCP_SKB_CB(skb)->seq + 1;
 	TCP_SKB_CB(skb)->sacked = 0;
-	skb_shinfo(skb)->tso_segs = 1;
-	skb_shinfo(skb)->tso_size = 0;
+	skb_shinfo(skb)->gso_segs = 1;
+	skb_shinfo(skb)->gso_size = 0;
+	skb_shinfo(skb)->gso_type = 0;
 	th->seq = htonl(TCP_SKB_CB(skb)->seq);
 	th->ack_seq = htonl(tcp_rsk(req)->rcv_isn + 1);
 	if (req->rcv_wnd == 0) { /* ignored for retransmitted syns */
@@ -2152,8 +2158,9 @@ int tcp_connect(struct sock *sk)
 	TCP_SKB_CB(buff)->flags = TCPCB_FLAG_SYN;
 	TCP_ECN_send_syn(sk, tp, buff);
 	TCP_SKB_CB(buff)->sacked = 0;
-	skb_shinfo(buff)->tso_segs = 1;
-	skb_shinfo(buff)->tso_size = 0;
+	skb_shinfo(buff)->gso_segs = 1;
+	skb_shinfo(buff)->gso_size = 0;
+	skb_shinfo(buff)->gso_type = 0;
 	buff->csum = 0;
 	TCP_SKB_CB(buff)->seq = tp->write_seq++;
 	TCP_SKB_CB(buff)->end_seq = tp->write_seq;
@@ -2257,8 +2264,9 @@ void tcp_send_ack(struct sock *sk)
 		buff->csum = 0;
 		TCP_SKB_CB(buff)->flags = TCPCB_FLAG_ACK;
 		TCP_SKB_CB(buff)->sacked = 0;
-		skb_shinfo(buff)->tso_segs = 1;
-		skb_shinfo(buff)->tso_size = 0;
+		skb_shinfo(buff)->gso_segs = 1;
+		skb_shinfo(buff)->gso_size = 0;
+		skb_shinfo(buff)->gso_type = 0;
 
 		/* Send it off, this clears delayed acks for us. */
 		TCP_SKB_CB(buff)->seq = TCP_SKB_CB(buff)->end_seq = tcp_acceptable_seq(sk, tp);
@@ -2293,8 +2301,9 @@ static int tcp_xmit_probe_skb(struct sock *sk, int urgent)
 	skb->csum = 0;
 	TCP_SKB_CB(skb)->flags = TCPCB_FLAG_ACK;
 	TCP_SKB_CB(skb)->sacked = urgent;
-	skb_shinfo(skb)->tso_segs = 1;
-	skb_shinfo(skb)->tso_size = 0;
+	skb_shinfo(skb)->gso_segs = 1;
+	skb_shinfo(skb)->gso_size = 0;
+	skb_shinfo(skb)->gso_type = 0;
 
 	/* Use a previous sequence.  This should cause the other
 	 * end to send an ack.  Don't queue or clone SKB, just