net/core/tso.c

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