linux-stable/net/core/tso.c
Eric Dumazet 3d5b459ba0 net: tso: add UDP segmentation support
Note that like TCP, we do not support additional encapsulations,
and that checksums must be offloaded to the NIC.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2020-06-18 20:46:23 -07:00

97 lines
2.6 KiB
C

// SPDX-License-Identifier: GPL-2.0
#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(const 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(const struct sk_buff *skb, char *hdr, struct tso_t *tso,
int size, bool is_last)
{
int hdr_len = skb_transport_offset(skb) + tso->tlen;
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 + tso->tlen);
}
hdr += skb_transport_offset(skb);
if (tso->tlen != sizeof(struct udphdr)) {
struct tcphdr *tcph = (struct tcphdr *)hdr;
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;
}
} else {
struct udphdr *uh = (struct udphdr *)hdr;
uh->len = htons(sizeof(*uh) + size);
}
}
EXPORT_SYMBOL(tso_build_hdr);
void tso_build_data(const struct sk_buff *skb, struct tso_t *tso, int size)
{
tso->tcp_seq += size; /* not worth avoiding this operation for UDP */
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 = skb_frag_size(frag);
tso->data = skb_frag_address(frag);
tso->next_frag_idx++;
}
}
EXPORT_SYMBOL(tso_build_data);
int tso_start(struct sk_buff *skb, struct tso_t *tso)
{
int tlen = skb_is_gso_tcp(skb) ? tcp_hdrlen(skb) : sizeof(struct udphdr);
int hdr_len = skb_transport_offset(skb) + tlen;
tso->tlen = tlen;
tso->ip_id = ntohs(ip_hdr(skb)->id);
tso->tcp_seq = (tlen != sizeof(struct udphdr)) ? ntohl(tcp_hdr(skb)->seq) : 0;
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 = skb_frag_size(frag);
tso->data = skb_frag_address(frag);
tso->next_frag_idx++;
}
return hdr_len;
}
EXPORT_SYMBOL(tso_start);