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 */
7int 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}
12EXPORT_SYMBOL(tso_count_descs);
13
14void 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}
37EXPORT_SYMBOL(tso_build_hdr);
38
39void 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}
55EXPORT_SYMBOL(tso_build_data);
56
57void 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}
78EXPORT_SYMBOL(tso_start);
79