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