/* We cannot use oldskb->dev, it can be either bridge device (NF_BRIDGE INPUT)
* or the bridge port (NF_BRIDGE PREROUTING).
*/
static void nft_reject_br_send_v4_tcp_reset(struct net *net,
struct sk_buff *oldskb,
const struct net_device *dev,
int hook)
{
struct sk_buff *nskb;
struct iphdr *niph;
const struct tcphdr *oth;
struct tcphdr _oth;
if (!nft_bridge_iphdr_validate(oldskb))
return;
oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
if (!oth)
return;
nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
LL_MAX_HEADER, GFP_ATOMIC);
if (!nskb)
return;
skb_reserve(nskb, LL_MAX_HEADER);
niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
net->ipv4.sysctl_ip_default_ttl);
nf_reject_ip_tcphdr_put(nskb, oldskb, oth);
niph->ttl = net->ipv4.sysctl_ip_default_ttl;
niph->tot_len = htons(nskb->len);
ip_send_check(niph);
nft_reject_br_push_etherhdr(oldskb, nskb);
br_forward(br_port_get_rcu(dev), nskb, false, true);
}
static void nft_reject_br_send_v6_tcp_reset(struct net *net,
struct sk_buff *oldskb,
const struct net_device *dev,
int hook)
{
struct sk_buff *nskb;
const struct tcphdr *oth;
struct tcphdr _oth;
unsigned int otcplen;
struct ipv6hdr *nip6h;
if (!nft_bridge_ip6hdr_validate(oldskb))
return;
oth = nf_reject_ip6_tcphdr_get(oldskb, &_oth, &otcplen, hook);
if (!oth)
return;
nskb = alloc_skb(sizeof(struct ipv6hdr) + sizeof(struct tcphdr) +
LL_MAX_HEADER, GFP_ATOMIC);
if (!nskb)
return;
skb_reserve(nskb, LL_MAX_HEADER);
nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_TCP,
net->ipv6.devconf_all->hop_limit);
nf_reject_ip6_tcphdr_put(nskb, oldskb, oth, otcplen);
nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
nft_reject_br_push_etherhdr(oldskb, nskb);
br_forward(br_port_get_rcu(dev), nskb, false, true);
}
static void nft_reject_br_send_v6_unreach(struct net *net,
struct sk_buff *oldskb,
const struct net_device *dev,
int hook, u8 code)
{
struct sk_buff *nskb;
struct ipv6hdr *nip6h;
struct icmp6hdr *icmp6h;
unsigned int len;
void *payload;
if (!nft_bridge_ip6hdr_validate(oldskb))
return;
/* Include "As much of invoking packet as possible without the ICMPv6
* packet exceeding the minimum IPv6 MTU" in the ICMP payload.
*/
len = min_t(unsigned int, 1220, oldskb->len);
if (!pskb_may_pull(oldskb, len))
return;
if (!reject6_br_csum_ok(oldskb, hook))
return;
nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmp6hdr) +
LL_MAX_HEADER + len, GFP_ATOMIC);
if (!nskb)
return;
skb_reserve(nskb, LL_MAX_HEADER);
nip6h = nf_reject_ip6hdr_put(nskb, oldskb, IPPROTO_ICMPV6,
net->ipv6.devconf_all->hop_limit);
skb_reset_transport_header(nskb);
icmp6h = (struct icmp6hdr *)skb_put(nskb, sizeof(struct icmp6hdr));
memset(icmp6h, 0, sizeof(*icmp6h));
icmp6h->icmp6_type = ICMPV6_DEST_UNREACH;
icmp6h->icmp6_code = code;
payload = skb_put(nskb, len);
memcpy(payload, skb_network_header(oldskb), len);
nip6h->payload_len = htons(nskb->len - sizeof(struct ipv6hdr));
icmp6h->icmp6_cksum =
csum_ipv6_magic(&nip6h->saddr, &nip6h->daddr,
nskb->len - sizeof(struct ipv6hdr),
IPPROTO_ICMPV6,
csum_partial(icmp6h,
nskb->len - sizeof(struct ipv6hdr),
0));
nft_reject_br_push_etherhdr(oldskb, nskb);
br_forward(br_port_get_rcu(dev), nskb, false, true);
}
static void nft_reject_br_send_v4_unreach(struct sk_buff *oldskb, int hook,
u8 code)
{
struct sk_buff *nskb;
struct iphdr *niph;
struct icmphdr *icmph;
unsigned int len;
void *payload;
__wsum csum;
if (!nft_reject_iphdr_validate(oldskb))
return;
/* IP header checks: fragment. */
if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
return;
/* RFC says return as much as we can without exceeding 576 bytes. */
len = min_t(unsigned int, 536, oldskb->len);
if (!pskb_may_pull(oldskb, len))
return;
if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), 0))
return;
nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
LL_MAX_HEADER + len, GFP_ATOMIC);
if (!nskb)
return;
skb_reserve(nskb, LL_MAX_HEADER);
niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
sysctl_ip_default_ttl);
skb_reset_transport_header(nskb);
icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
memset(icmph, 0, sizeof(*icmph));
icmph->type = ICMP_DEST_UNREACH;
icmph->code = code;
payload = skb_put(nskb, len);
memcpy(payload, skb_network_header(oldskb), len);
csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
icmph->checksum = csum_fold(csum);
niph->tot_len = htons(nskb->len);
ip_send_check(niph);
nft_reject_br_push_etherhdr(oldskb, nskb);
br_deliver(br_port_get_rcu(oldskb->dev), nskb);
}
static void nft_reject_br_send_v4_unreach(struct net *net,
struct sk_buff *oldskb,
const struct net_device *dev,
int hook, u8 code)
{
struct sk_buff *nskb;
struct iphdr *niph;
struct icmphdr *icmph;
unsigned int len;
void *payload;
__wsum csum;
u8 proto;
if (oldskb->csum_bad || !nft_bridge_iphdr_validate(oldskb))
return;
/* IP header checks: fragment. */
if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
return;
/* RFC says return as much as we can without exceeding 576 bytes. */
len = min_t(unsigned int, 536, oldskb->len);
if (!pskb_may_pull(oldskb, len))
return;
if (pskb_trim_rcsum(oldskb, ntohs(ip_hdr(oldskb)->tot_len)))
return;
if (ip_hdr(oldskb)->protocol == IPPROTO_TCP ||
ip_hdr(oldskb)->protocol == IPPROTO_UDP)
proto = ip_hdr(oldskb)->protocol;
else
proto = 0;
if (!skb_csum_unnecessary(oldskb) &&
nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), proto))
return;
nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct icmphdr) +
LL_MAX_HEADER + len, GFP_ATOMIC);
if (!nskb)
return;
skb_reserve(nskb, LL_MAX_HEADER);
niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_ICMP,
net->ipv4.sysctl_ip_default_ttl);
skb_reset_transport_header(nskb);
icmph = (struct icmphdr *)skb_put(nskb, sizeof(struct icmphdr));
memset(icmph, 0, sizeof(*icmph));
icmph->type = ICMP_DEST_UNREACH;
icmph->code = code;
payload = skb_put(nskb, len);
memcpy(payload, skb_network_header(oldskb), len);
csum = csum_partial((void *)icmph, len + sizeof(struct icmphdr), 0);
icmph->checksum = csum_fold(csum);
niph->tot_len = htons(nskb->len);
ip_send_check(niph);
nft_reject_br_push_etherhdr(oldskb, nskb);
br_forward(br_port_get_rcu(dev), nskb, false, true);
}
