LXR linux/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 */
   8int 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}
  13EXPORT_SYMBOL(tso_count_descs);
  14
  15void 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}
  44EXPORT_SYMBOL(tso_build_hdr);
  45
  46void 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;
  55
  56                gmb();
  57                frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  58
  59                /* Move to next segment */
  60                tso->size = frag->size;
  61                tso->data = page_address(frag->page.p) + frag->page_offset;
  62                tso->next_frag_idx++;
  63        }
  64}
  65EXPORT_SYMBOL(tso_build_data);
  66
  67void tso_start(struct sk_buff *skb, struct tso_t *tso)
  68{
  69        int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
  70
  71        tso->ip_id = ntohs(ip_hdr(skb)->id);
  72        tso->tcp_seq = ntohl(tcp_hdr(skb)->seq);
  73        tso->next_frag_idx = 0;
  74        tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);
  75
  76        /* Build first data */
  77        tso->size = skb_headlen(skb) - hdr_len;
  78        tso->data = skb->data + hdr_len;
  79        if ((tso->size == 0) &&
  80            (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  81                skb_frag_t *frag;
  82
  83                gmb();
  84                frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  85                /* Move to next segment */
  86                tso->size = frag->size;
  87                tso->data = page_address(frag->page.p) + frag->page_offset;
  88                tso->next_frag_idx++;
  89        }
  90}
  91EXPORT_SYMBOL(tso_start);
  92