Exemplos de nf_reject_ip_tcphdr_get em C++ (Cpp)

Exemplo n.º 1

Arquivo: nft_reject_bridge.c Projeto: asmalldev/linux

/* 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);
}

Exemplo n.º 2

Arquivo: nf_reject_ipv4.c Projeto: Lyude/linux

/* Send RST reply */
void nf_send_reset(struct net *net, struct sk_buff *oldskb, int hook)
{
	struct sk_buff *nskb;
	struct iphdr *niph;
	const struct tcphdr *oth;
	struct tcphdr _oth;

	oth = nf_reject_ip_tcphdr_get(oldskb, &_oth, hook);
	if (!oth)
		return;

	if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
		return;

	nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
			 LL_MAX_HEADER, GFP_ATOMIC);
	if (!nskb)
		return;

	/* ip_route_me_harder expects skb->dst to be set */
	skb_dst_set_noref(nskb, skb_dst(oldskb));

	nskb->mark = IP4_REPLY_MARK(net, oldskb->mark);

	skb_reserve(nskb, LL_MAX_HEADER);
	niph = nf_reject_iphdr_put(nskb, oldskb, IPPROTO_TCP,
				   ip4_dst_hoplimit(skb_dst(nskb)));
	nf_reject_ip_tcphdr_put(nskb, oldskb, oth);

	if (ip_route_me_harder(net, nskb, RTN_UNSPEC))
		goto free_nskb;

	niph = ip_hdr(nskb);

	/* "Never happens" */
	if (nskb->len > dst_mtu(skb_dst(nskb)))
		goto free_nskb;

	nf_ct_attach(nskb, oldskb);

#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
	/* If we use ip_local_out for bridged traffic, the MAC source on
	 * the RST will be ours, instead of the destination's.  This confuses
	 * some routers/firewalls, and they drop the packet.  So we need to
	 * build the eth header using the original destination's MAC as the
	 * source, and send the RST packet directly.
	 */
	if (oldskb->nf_bridge) {
		struct ethhdr *oeth = eth_hdr(oldskb);

		nskb->dev = nf_bridge_get_physindev(oldskb);
		niph->tot_len = htons(nskb->len);
		ip_send_check(niph);
		if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol),
				    oeth->h_source, oeth->h_dest, nskb->len) < 0)
			goto free_nskb;
		dev_queue_xmit(nskb);
	} else
#endif
		ip_local_out(net, nskb->sk, nskb);

	return;

 free_nskb:
	kfree_skb(nskb);
}