LXR linux/net/core/tso.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/export.h>
   3#include <linux/if_vlan.h>
   4#include <net/ip.h>
   5#include <net/tso.h>
   6#include <asm/unaligned.h>
   7
   8/* Calculate expected number of TX descriptors */
   9int tso_count_descs(struct sk_buff *skb)
  10{
  11        /* The Marvell Way */
  12        return skb_shinfo(skb)->gso_segs * 2 + skb_shinfo(skb)->nr_frags;
  13}
  14EXPORT_SYMBOL(tso_count_descs);
  15
  16void tso_build_hdr(struct sk_buff *skb, char *hdr, struct tso_t *tso,
  17                   int size, bool is_last)
  18{
  19        struct tcphdr *tcph;
  20        int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
  21        int mac_hdr_len = skb_network_offset(skb);
  22
  23        memcpy(hdr, skb->data, hdr_len);
  24        if (!tso->ipv6) {
  25                struct iphdr *iph = (void *)(hdr + mac_hdr_len);
  26
  27                iph->id = htons(tso->ip_id);
  28                iph->tot_len = htons(size + hdr_len - mac_hdr_len);
  29                tso->ip_id++;
  30        } else {
  31                struct ipv6hdr *iph = (void *)(hdr + mac_hdr_len);
  32
  33                iph->payload_len = htons(size + tcp_hdrlen(skb));
  34        }
  35        tcph = (struct tcphdr *)(hdr + skb_transport_offset(skb));
  36        put_unaligned_be32(tso->tcp_seq, &tcph->seq);
  37
  38        if (!is_last) {
  39                /* Clear all special flags for not last packet */
  40                tcph->psh = 0;
  41                tcph->fin = 0;
  42                tcph->rst = 0;
  43        }
  44}
  45EXPORT_SYMBOL(tso_build_hdr);
  46
  47void tso_build_data(struct sk_buff *skb, struct tso_t *tso, int size)
  48{
  49        tso->tcp_seq += size;
  50        tso->size -= size;
  51        tso->data += size;
  52
  53        if ((tso->size == 0) &&
  54            (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  55                skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  56
  57                /* Move to next segment */
  58                tso->size = frag->size;
  59                tso->data = page_address(frag->page.p) + frag->page_offset;
  60                tso->next_frag_idx++;
  61        }
  62}
  63EXPORT_SYMBOL(tso_build_data);
  64
  65void tso_start(struct sk_buff *skb, struct tso_t *tso)
  66{
  67        int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
  68
  69        tso->ip_id = ntohs(ip_hdr(skb)->id);
  70        tso->tcp_seq = ntohl(tcp_hdr(skb)->seq);
  71        tso->next_frag_idx = 0;
  72        tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);
  73
  74        /* Build first data */
  75        tso->size = skb_headlen(skb) - hdr_len;
  76        tso->data = skb->data + hdr_len;
  77        if ((tso->size == 0) &&
  78            (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  79                skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  80
  81                /* Move to next segment */
  82                tso->size = frag->size;
  83                tso->data = page_address(frag->page.p) + frag->page_offset;
  84                tso->next_frag_idx++;
  85        }
  86}
  87EXPORT_SYMBOL(tso_start);
  88