net: tso: add UDP segmentation support

Note that like TCP, we do not support additional encapsulations,
and that checksums must be offloaded to the NIC.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/net/core/tso.c b/net/core/tso.c
index 9f35518..4148f6d 100644 (file)
--- a/net/core/tso.c
+++ b/net/core/tso.c
@@ -16,7 +16,6 @@ EXPORT_SYMBOL(tso_count_descs);
 void tso_build_hdr(const struct sk_buff *skb, char *hdr, struct tso_t *tso,
                   int size, bool is_last)
 {
-       struct tcphdr *tcph;
        int hdr_len = skb_transport_offset(skb) + tso->tlen;
        int mac_hdr_len = skb_network_offset(skb);
 
@@ -32,21 +31,29 @@ void tso_build_hdr(const struct sk_buff *skb, char *hdr, struct tso_t *tso,
 
                iph->payload_len = htons(size + tso->tlen);
        }
-       tcph = (struct tcphdr *)(hdr + skb_transport_offset(skb));
-       put_unaligned_be32(tso->tcp_seq, &tcph->seq);
+       hdr += skb_transport_offset(skb);
+       if (tso->tlen != sizeof(struct udphdr)) {
+               struct tcphdr *tcph = (struct tcphdr *)hdr;
 
-       if (!is_last) {
-               /* Clear all special flags for not last packet */
-               tcph->psh = 0;
-               tcph->fin = 0;
-               tcph->rst = 0;
+               put_unaligned_be32(tso->tcp_seq, &tcph->seq);
+
+               if (!is_last) {
+                       /* Clear all special flags for not last packet */
+                       tcph->psh = 0;
+                       tcph->fin = 0;
+                       tcph->rst = 0;
+               }
+       } else {
+               struct udphdr *uh = (struct udphdr *)hdr;
+
+               uh->len = htons(sizeof(*uh) + size);
        }
 }
 EXPORT_SYMBOL(tso_build_hdr);
 
 void tso_build_data(const struct sk_buff *skb, struct tso_t *tso, int size)
 {
-       tso->tcp_seq += size;
+       tso->tcp_seq += size; /* not worth avoiding this operation for UDP */
        tso->size -= size;
        tso->data += size;
 
@@ -64,12 +71,12 @@ EXPORT_SYMBOL(tso_build_data);
 
 int tso_start(struct sk_buff *skb, struct tso_t *tso)
 {
-       int tlen = tcp_hdrlen(skb);
+       int tlen = skb_is_gso_tcp(skb) ? tcp_hdrlen(skb) : sizeof(struct udphdr);
        int hdr_len = skb_transport_offset(skb) + tlen;
 
        tso->tlen = tlen;
        tso->ip_id = ntohs(ip_hdr(skb)->id);
-       tso->tcp_seq = ntohl(tcp_hdr(skb)->seq);
+       tso->tcp_seq = (tlen != sizeof(struct udphdr)) ? ntohl(tcp_hdr(skb)->seq) : 0;
        tso->next_frag_idx = 0;
        tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);