tso.c
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#include <linux/export.h>
#include <linux/if_vlan.h>
#include <net/ip.h>
#include <net/tso.h>
#include <asm/unaligned.h>
/* Calculate expected number of TX descriptors */
int tso_count_descs(struct sk_buff *skb)
{
/* The Marvell Way */
return skb_shinfo(skb)->gso_segs * 2 + skb_shinfo(skb)->nr_frags;
}
EXPORT_SYMBOL(tso_count_descs);
void tso_build_hdr(struct sk_buff *skb, char *hdr, struct tso_t *tso,
int size, bool is_last)
{
struct tcphdr *tcph;
int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
int mac_hdr_len = skb_network_offset(skb);
memcpy(hdr, skb->data, hdr_len);
if (!tso->ipv6) {
struct iphdr *iph = (void *)(hdr + mac_hdr_len);
iph->id = htons(tso->ip_id);
iph->tot_len = htons(size + hdr_len - mac_hdr_len);
tso->ip_id++;
} else {
struct ipv6hdr *iph = (void *)(hdr + mac_hdr_len);
iph->payload_len = htons(size + tcp_hdrlen(skb));
}
tcph = (struct tcphdr *)(hdr + skb_transport_offset(skb));
put_unaligned_be32(tso->tcp_seq, &tcph->seq);
if (!is_last) {
/* Clear all special flags for not last packet */
tcph->psh = 0;
tcph->fin = 0;
tcph->rst = 0;
}
}
EXPORT_SYMBOL(tso_build_hdr);
void tso_build_data(struct sk_buff *skb, struct tso_t *tso, int size)
{
tso->tcp_seq += size;
tso->size -= size;
tso->data += size;
if ((tso->size == 0) &&
(tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
/* Move to next segment */
tso->size = frag->size;
tso->data = page_address(frag->page.p) + frag->page_offset;
tso->next_frag_idx++;
}
}
EXPORT_SYMBOL(tso_build_data);
void tso_start(struct sk_buff *skb, struct tso_t *tso)
{
int hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
tso->ip_id = ntohs(ip_hdr(skb)->id);
tso->tcp_seq = ntohl(tcp_hdr(skb)->seq);
tso->next_frag_idx = 0;
tso->ipv6 = vlan_get_protocol(skb) == htons(ETH_P_IPV6);
/* Build first data */
tso->size = skb_headlen(skb) - hdr_len;
tso->data = skb->data + hdr_len;
if ((tso->size == 0) &&
(tso->next_frag_idx < skb_shinfo(skb)->nr_frags)) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[tso->next_frag_idx];
/* Move to next segment */
tso->size = frag->size;
tso->data = page_address(frag->page.p) + frag->page_offset;
tso->next_frag_idx++;
}
}
EXPORT_SYMBOL(tso_start);