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(const 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(const struct sk_buff *skb, char *hdr, struct tso_t *tso,
  17                   int size, bool is_last)
  18{
  19        int hdr_len = skb_transport_offset(skb) + tso->tlen;
  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 + tso->tlen);
  33        }
  34        hdr += skb_transport_offset(skb);
  35        if (tso->tlen != sizeof(struct udphdr)) {
  36                struct tcphdr *tcph = (struct tcphdr *)hdr;
  37
  38                put_unaligned_be32(tso->tcp_seq, &tcph->seq);
  39
  40                if (!is_last) {
  41                        /* Clear all special flags for not last packet */
  42                        tcph->psh = 0;
  43                        tcph->fin = 0;
  44                        tcph->rst = 0;
  45                }
  46        } else {
  47                struct udphdr *uh = (struct udphdr *)hdr;
  48
  49                uh->len = htons(sizeof(*uh) + size);
  50        }
  51}
  52EXPORT_SYMBOL(tso_build_hdr);
  53
  54void tso_build_data(const struct sk_buff *skb, struct tso_t *tso, int size)
  55{
  56        tso->tcp_seq += size; /* not worth avoiding this operation for UDP */
  57        tso->size -= size;
  58        tso->data += size;
  59
  60        if ((tso->size == 0) &&
  61            (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  62                skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  63
  64                /* Move to next segment */
  65                tso->size = skb_frag_size(frag);
  66                tso->data = skb_frag_address(frag);
  67                tso->next_frag_idx++;
  68        }
  69}
  70EXPORT_SYMBOL(tso_build_data);
  71
  72int tso_start(struct sk_buff *skb, struct tso_t *tso)
  73{
  74        int tlen = skb_is_gso_tcp(skb) ? tcp_hdrlen(skb) : sizeof(struct udphdr);
  75        int hdr_len = skb_transport_offset(skb) + tlen;
  76
  77        tso->tlen = tlen;
  78        tso->ip_id = ntohs(ip_hdr(skb)->id);
  79        tso->tcp_seq = (tlen != sizeof(struct udphdr)) ? ntohl(tcp_hdr(skb)->seq) : 0;
  80        tso->next_frag_idx = 0;
  81        tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);
  82
  83        /* Build first data */
  84        tso->size = skb_headlen(skb) - hdr_len;
  85        tso->data = skb->data + hdr_len;
  86        if ((tso->size == 0) &&
  87            (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
  88                skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
  89
  90                /* Move to next segment */
  91                tso->size = skb_frag_size(frag);
  92                tso->data = skb_frag_address(frag);
  93                tso->next_frag_idx++;
  94        }
  95        return hdr_len;
  96}
  97EXPORT_SYMBOL(tso_start);
  98