net/core/tso.c

   1 #include <linux/export.h>
   2 #include <linux/if_vlan.h>
   3 #include <net/ip.h>
   4 #include <net/tso.h>
   5 #include <asm/unaligned.h>
   6
   7 /* Calculate expected number of TX descriptors */
   8 int tso_count_descs(struct sk_buff *skb)
   9 {
  10         /* The Marvell Way */
  11         return skb_shinfo(skb)->gso_segs * 2 + skb_shinfo(skb)->nr_frags;
  12 }
  13 EXPORT_SYMBOL(tso_count_descs);
  14
  15 void tso_build_hdr(struct sk_buff *skb, char *hdr, struct tso_t *tso,
  16                    int size, bool is_last)
  17 {
  18         struct tcphdr *tcph;
  19         int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
  20         int mac_hdr_len = skb_network_offset(skb);
  21
  22         memcpy(hdr, skb->data, hdr_len);
  23         if (!tso->ipv6) {
  24                 struct iphdr *iph = (void *)(hdr + mac_hdr_len);
  25
  26                 iph->id = htons(tso->ip_id);
  27                 iph->tot_len = htons(size + hdr_len - mac_hdr_len);
  28                 tso->ip_id++;
  29         } else {
  30                 struct ipv6hdr *iph = (void *)(hdr + mac_hdr_len);
  31
  32                 iph->payload_len = htons(size + tcp_hdrlen(skb));
  33         }
  34         tcph = (struct tcphdr *)(hdr + skb_transport_offset(skb));
  35         put_unaligned_be32(tso->tcp_seq, &tcph->seq);
  36
  37         if (!is_last) {
  38                 /* Clear all special flags for not last packet */
  39                 tcph->psh = 0;
  40                 tcph->fin = 0;
  41                 tcph->rst = 0;
  42         }
  43 }
  44 EXPORT_SYMBOL(tso_build_hdr);
  45
  46 void tso_build_data(struct sk_buff *skb, struct tso_t *tso, int size)
  47 {
  48         tso->tcp_seq += size;
  49         tso->size -= size;
  50         tso->data += size;
  51
  52         if ((tso->size == 0) &&
  53             (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  54                 skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  55
  56                 /* Move to next segment */
  57                 tso->size = frag->size;
  58                 tso->data = page_address(frag->page.p) + frag->page_offset;
  59                 tso->next_frag_idx++;
  60         }
  61 }
  62 EXPORT_SYMBOL(tso_build_data);
  63
  64 void tso_start(struct sk_buff *skb, struct tso_t *tso)
  65 {
  66         int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
  67
  68         tso->ip_id = ntohs(ip_hdr(skb)->id);
  69         tso->tcp_seq = ntohl(tcp_hdr(skb)->seq);
  70         tso->next_frag_idx = 0;
  71         tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);
  72
  73         /* Build first data */
  74         tso->size = skb_headlen(skb) - hdr_len;
  75         tso->data = skb->data + hdr_len;
  76         if ((tso->size == 0) &&
  77             (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  78                 skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  79
  80                 /* Move to next segment */
  81                 tso->size = frag->size;
  82                 tso->data = page_address(frag->page.p) + frag->page_offset;
  83                 tso->next_frag_idx++;
  84         }
  85 }
  86 EXPORT_SYMBOL(tso_start);