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 <linux/unaligned.h>
7
8void tso_build_hdr(const struct sk_buff *skb, char *hdr, struct tso_t *tso,
9 int size, bool is_last)
10{
11 int hdr_len = skb_transport_offset(skb) + tso->tlen;
12 int mac_hdr_len = skb_network_offset(skb);
13
14 memcpy(hdr, skb->data, hdr_len);
15 if (!tso->ipv6) {
16 struct iphdr *iph = (void *)(hdr + mac_hdr_len);
17
18 iph->id = htons(tso->ip_id);
19 iph->tot_len = htons(size + hdr_len - mac_hdr_len);
20 tso->ip_id++;
21 } else {
22 struct ipv6hdr *iph = (void *)(hdr + mac_hdr_len);
23
24 iph->payload_len = htons(size + tso->tlen);
25 }
26 hdr += skb_transport_offset(skb);
27 if (tso->tlen != sizeof(struct udphdr)) {
28 struct tcphdr *tcph = (struct tcphdr *)hdr;
29
30 put_unaligned_be32(val: tso->tcp_seq, p: &tcph->seq);
31
32 if (!is_last) {
33 /* Clear all special flags for not last packet */
34 tcph->psh = 0;
35 tcph->fin = 0;
36 tcph->rst = 0;
37 }
38 } else {
39 struct udphdr *uh = (struct udphdr *)hdr;
40
41 uh->len = htons(sizeof(*uh) + size);
42 }
43}
44EXPORT_SYMBOL(tso_build_hdr);
45
46void tso_build_data(const struct sk_buff *skb, struct tso_t *tso, int size)
47{
48 tso->tcp_seq += size; /* not worth avoiding this operation for UDP */
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 = skb_frag_size(frag);
58 tso->data = skb_frag_address(frag);
59 tso->next_frag_idx++;
60 }
61}
62EXPORT_SYMBOL(tso_build_data);
63
64int tso_start(struct sk_buff *skb, struct tso_t *tso)
65{
66 int tlen = skb_is_gso_tcp(skb) ? tcp_hdrlen(skb) : sizeof(struct udphdr);
67 int hdr_len = skb_transport_offset(skb) + tlen;
68
69 tso->tlen = tlen;
70 tso->ip_id = ntohs(ip_hdr(skb)->id);
71 tso->tcp_seq = (tlen != sizeof(struct udphdr)) ? ntohl(tcp_hdr(skb)->seq) : 0;
72 tso->next_frag_idx = 0;
73 tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);
74
75 /* Build first data */
76 tso->size = skb_headlen(skb) - hdr_len;
77 tso->data = skb->data + hdr_len;
78 if ((tso->size == 0) &&
79 (tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
80 skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
81
82 /* Move to next segment */
83 tso->size = skb_frag_size(frag);
84 tso->data = skb_frag_address(frag);
85 tso->next_frag_idx++;
86 }
87 return hdr_len;
88}
89EXPORT_SYMBOL(tso_start);
90

source code of linux/net/core/tso.c