static void lro_update_tcp_ip_header(struct net_lro_desc *lro_desc)
{
struct iphdr *iph = lro_desc->iph;
struct tcphdr *tcph = lro_desc->tcph;
__be32 *p;
__wsum tcp_hdr_csum;
tcph->ack_seq = lro_desc->tcp_ack;
tcph->window = lro_desc->tcp_window;
if (lro_desc->tcp_saw_tstamp) {
p = (__be32 *)(tcph + 1);
*(p+2) = lro_desc->tcp_rcv_tsecr;
}
csum_replace2(&iph->check, iph->tot_len, htons(lro_desc->ip_tot_len));
iph->tot_len = htons(lro_desc->ip_tot_len);
tcph->check = 0;
tcp_hdr_csum = csum_partial((u8 *)tcph, TCP_HDR_LEN(tcph), 0);
lro_desc->data_csum = csum_add(lro_desc->data_csum, tcp_hdr_csum);
tcph->check = csum_tcpudp_magic(iph->saddr, iph->daddr,
lro_desc->ip_tot_len -
IP_HDR_LEN(iph), IPPROTO_TCP,
lro_desc->data_csum);
}
static void udpencap_fix4(struct sk_buff *skb, const struct xt_udpencap_tginfo *info)
{
struct iphdr *iph = ip_hdr(skb);
bool fix_csum = (skb->ip_summed == CHECKSUM_COMPLETE && !info->encap);
__be16 newlen = htons(ntohs(iph->tot_len) + (info->encap ? 1 : -1) * sizeof(struct udphdr));
if (fix_csum) {
skb->csum = csum_sub(skb->csum, csum_partial(&iph->tot_len, 2, 0));
skb->csum = csum_sub(skb->csum, csum_partial(&iph->protocol, 3, 0));
}
csum_replace2(&iph->check, iph->tot_len, newlen);
iph->tot_len = newlen;
if (iph->protocol != info->proto) {
csum_replace2(&iph->check, htons(iph->protocol), htons(info->proto));
iph->protocol = info->proto;
}
if (fix_csum) {
skb->csum = csum_add(skb->csum, csum_partial(&iph->tot_len, 2, 0));
skb->csum = csum_add(skb->csum, csum_partial(&iph->protocol, 3, 0));
}
}
static bool mpls_egress(struct mpls_route *rt, struct sk_buff *skb,
struct mpls_entry_decoded dec)
{
/* RFC4385 and RFC5586 encode other packets in mpls such that
* they don't conflict with the ip version number, making
* decoding by examining the ip version correct in everything
* except for the strangest cases.
*
* The strange cases if we choose to support them will require
* manual configuration.
*/
struct iphdr *hdr4;
bool success = true;
/* The IPv4 code below accesses through the IPv4 header
* checksum, which is 12 bytes into the packet.
* The IPv6 code below accesses through the IPv6 hop limit
* which is 8 bytes into the packet.
*
* For all supported cases there should always be at least 12
* bytes of packet data present. The IPv4 header is 20 bytes
* without options and the IPv6 header is always 40 bytes
* long.
*/
if (!pskb_may_pull(skb, 12))
return false;
/* Use ip_hdr to find the ip protocol version */
hdr4 = ip_hdr(skb);
if (hdr4->version == 4) {
skb->protocol = htons(ETH_P_IP);
csum_replace2(&hdr4->check,
htons(hdr4->ttl << 8),
htons(dec.ttl << 8));
hdr4->ttl = dec.ttl;
}
else if (hdr4->version == 6) {
struct ipv6hdr *hdr6 = ipv6_hdr(skb);
skb->protocol = htons(ETH_P_IPV6);
hdr6->hop_limit = dec.ttl;
}
else
/* version 0 and version 1 are used by pseudo wires */
success = false;
return success;
}
/* set ECT codepoint from IP header.
* return false if there was an error. */
static inline bool
set_ect_ip(struct sk_buff *skb, const struct ipt_ECN_info *einfo)
{
struct iphdr *iph = ip_hdr(skb);
if ((iph->tos & IPT_ECN_IP_MASK) != (einfo->ip_ect & IPT_ECN_IP_MASK)) {
__u8 oldtos;
if (!skb_make_writable(skb, sizeof(struct iphdr)))
return false;
iph = ip_hdr(skb);
oldtos = iph->tos;
iph->tos &= ~IPT_ECN_IP_MASK;
iph->tos |= (einfo->ip_ect & IPT_ECN_IP_MASK);
csum_replace2(&iph->check, htons(oldtos), htons(iph->tos));
}
return true;
}
static void cvsw_apply_set_nw_tos(struct sk_buff *skb, const __u8 tos)
{
__u8 *nw;
nw = skb_util_get_network_header(skb);
if (unlikely(! nw)) {
return ;
}
if (((struct iphdr*)nw)->version == 4) {
off_t off;
struct iphdr *ip4;
ip4 = (struct iphdr*)nw;
off = offsetof(struct iphdr, tos);
/* Update L3 checksum */
csum_replace2(&ip4->check, htons(*((__u16*)&ip4->tos)), tos << 8 | nw[off + 1]);
/* Set ToS */
ip4->tos = tos;
} else if (((struct ipv6hdr*)nw)->version == 6) {
static unsigned int
ttl_tg(struct sk_buff *skb, const struct xt_action_param *par)
{
struct iphdr *iph;
const struct ipt_TTL_info *info = par->targinfo;
int new_ttl;
if (!skb_make_writable(skb, skb->len))
return NF_DROP;
iph = ip_hdr(skb);
switch (info->mode) {
case IPT_TTL_SET:
new_ttl = info->ttl;
break;
case IPT_TTL_INC:
new_ttl = iph->ttl + info->ttl;
if (new_ttl > 255)
new_ttl = 255;
break;
case IPT_TTL_DEC:
new_ttl = iph->ttl - info->ttl;
if (new_ttl < 0)
new_ttl = 0;
break;
default:
new_ttl = iph->ttl;
break;
}
if (new_ttl != iph->ttl) {
csum_replace2(&iph->check, htons(iph->ttl << 8),
htons(new_ttl << 8));
iph->ttl = new_ttl;
}
return XT_CONTINUE;
}
static void set_ip_ttl(struct sk_buff *skb, struct iphdr *nh, u8 new_ttl)
{
csum_replace2(&nh->check, htons(nh->ttl << 8), htons(new_ttl << 8));
nh->ttl = new_ttl;
}
