netfilter: move nf_send_resetX() code to nf_reject_ipvX modules
Move nf_send_reset() and nf_send_reset6() to nf_reject_ipv4 and nf_reject_ipv6 respectively. This code is shared by x_tables and nf_tables. Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>hifive-unleashed-5.1
Pablo Neira Ayuso
parent
51b0a5d8c2
commit
c8d7b98bec
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@ -1,10 +1,6 @@
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#ifndef _IPV4_NF_REJECT_H
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#define _IPV4_NF_REJECT_H
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#include <net/ip.h>
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#include <net/tcp.h>
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#include <net/route.h>
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#include <net/dst.h>
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#include <net/icmp.h>
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static inline void nf_send_unreach(struct sk_buff *skb_in, int code)
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@ -12,118 +8,6 @@ static inline void nf_send_unreach(struct sk_buff *skb_in, int code)
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icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0);
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}
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/* Send RST reply */
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static void nf_send_reset(struct sk_buff *oldskb, int hook)
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{
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struct sk_buff *nskb;
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const struct iphdr *oiph;
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struct iphdr *niph;
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const struct tcphdr *oth;
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struct tcphdr _otcph, *tcph;
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/* IP header checks: fragment. */
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if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
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return;
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oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
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sizeof(_otcph), &_otcph);
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if (oth == NULL)
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return;
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/* No RST for RST. */
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if (oth->rst)
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return;
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if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
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return;
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/* Check checksum */
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if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
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return;
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oiph = ip_hdr(oldskb);
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nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
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LL_MAX_HEADER, GFP_ATOMIC);
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if (!nskb)
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return;
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skb_reserve(nskb, LL_MAX_HEADER);
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skb_reset_network_header(nskb);
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niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
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niph->version = 4;
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niph->ihl = sizeof(struct iphdr) / 4;
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niph->tos = 0;
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niph->id = 0;
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niph->frag_off = htons(IP_DF);
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niph->protocol = IPPROTO_TCP;
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niph->check = 0;
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niph->saddr = oiph->daddr;
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niph->daddr = oiph->saddr;
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skb_reset_transport_header(nskb);
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tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
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memset(tcph, 0, sizeof(*tcph));
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tcph->source = oth->dest;
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tcph->dest = oth->source;
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tcph->doff = sizeof(struct tcphdr) / 4;
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if (oth->ack)
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tcph->seq = oth->ack_seq;
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else {
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tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
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oldskb->len - ip_hdrlen(oldskb) -
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(oth->doff << 2));
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tcph->ack = 1;
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}
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tcph->rst = 1;
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tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
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niph->daddr, 0);
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nskb->ip_summed = CHECKSUM_PARTIAL;
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nskb->csum_start = (unsigned char *)tcph - nskb->head;
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nskb->csum_offset = offsetof(struct tcphdr, check);
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/* ip_route_me_harder expects skb->dst to be set */
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skb_dst_set_noref(nskb, skb_dst(oldskb));
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nskb->protocol = htons(ETH_P_IP);
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if (ip_route_me_harder(nskb, RTN_UNSPEC))
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goto free_nskb;
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niph->ttl = ip4_dst_hoplimit(skb_dst(nskb));
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/* "Never happens" */
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if (nskb->len > dst_mtu(skb_dst(nskb)))
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goto free_nskb;
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nf_ct_attach(nskb, oldskb);
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#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
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/* If we use ip_local_out for bridged traffic, the MAC source on
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* the RST will be ours, instead of the destination's. This confuses
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* some routers/firewalls, and they drop the packet. So we need to
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* build the eth header using the original destination's MAC as the
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* source, and send the RST packet directly.
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*/
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if (oldskb->nf_bridge) {
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struct ethhdr *oeth = eth_hdr(oldskb);
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nskb->dev = oldskb->nf_bridge->physindev;
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niph->tot_len = htons(nskb->len);
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ip_send_check(niph);
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if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol),
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oeth->h_source, oeth->h_dest, nskb->len) < 0)
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goto free_nskb;
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dev_queue_xmit(nskb);
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} else
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#endif
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ip_local_out(nskb);
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return;
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free_nskb:
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kfree_skb(nskb);
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}
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void nf_send_reset(struct sk_buff *oldskb, int hook);
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#endif /* _IPV4_NF_REJECT_H */
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@ -61,8 +61,13 @@ config NFT_CHAIN_ROUTE_IPV4
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fields such as the source, destination, type of service and
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the packet mark.
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config NF_REJECT_IPV4
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tristate "IPv4 packet rejection"
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default m if NETFILTER_ADVANCED=n
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config NFT_REJECT_IPV4
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depends on NF_TABLES_IPV4
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select NF_REJECT_IPV4
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default NFT_REJECT
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tristate
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@ -208,6 +213,7 @@ config IP_NF_FILTER
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config IP_NF_TARGET_REJECT
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tristate "REJECT target support"
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depends on IP_NF_FILTER
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select NF_REJECT_IPV4
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default m if NETFILTER_ADVANCED=n
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help
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The REJECT target allows a filtering rule to specify that an ICMP
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@ -23,6 +23,9 @@ obj-$(CONFIG_NF_DEFRAG_IPV4) += nf_defrag_ipv4.o
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obj-$(CONFIG_NF_LOG_ARP) += nf_log_arp.o
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obj-$(CONFIG_NF_LOG_IPV4) += nf_log_ipv4.o
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# reject
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obj-$(CONFIG_NF_REJECT_IPV4) += nf_reject_ipv4.o
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# NAT helpers (nf_conntrack)
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obj-$(CONFIG_NF_NAT_H323) += nf_nat_h323.o
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obj-$(CONFIG_NF_NAT_PPTP) += nf_nat_pptp.o
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@ -0,0 +1,127 @@
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <net/ip.h>
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#include <net/tcp.h>
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#include <net/route.h>
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#include <net/dst.h>
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#include <linux/netfilter_ipv4.h>
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/* Send RST reply */
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void nf_send_reset(struct sk_buff *oldskb, int hook)
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{
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struct sk_buff *nskb;
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const struct iphdr *oiph;
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struct iphdr *niph;
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const struct tcphdr *oth;
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struct tcphdr _otcph, *tcph;
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/* IP header checks: fragment. */
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if (ip_hdr(oldskb)->frag_off & htons(IP_OFFSET))
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return;
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oth = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
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sizeof(_otcph), &_otcph);
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if (oth == NULL)
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return;
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/* No RST for RST. */
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if (oth->rst)
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return;
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if (skb_rtable(oldskb)->rt_flags & (RTCF_BROADCAST | RTCF_MULTICAST))
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return;
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/* Check checksum */
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if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
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return;
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oiph = ip_hdr(oldskb);
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nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
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LL_MAX_HEADER, GFP_ATOMIC);
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if (!nskb)
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return;
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skb_reserve(nskb, LL_MAX_HEADER);
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skb_reset_network_header(nskb);
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niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
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niph->version = 4;
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niph->ihl = sizeof(struct iphdr) / 4;
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niph->tos = 0;
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niph->id = 0;
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niph->frag_off = htons(IP_DF);
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niph->protocol = IPPROTO_TCP;
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niph->check = 0;
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niph->saddr = oiph->daddr;
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niph->daddr = oiph->saddr;
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skb_reset_transport_header(nskb);
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tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
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memset(tcph, 0, sizeof(*tcph));
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tcph->source = oth->dest;
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tcph->dest = oth->source;
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tcph->doff = sizeof(struct tcphdr) / 4;
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if (oth->ack)
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tcph->seq = oth->ack_seq;
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else {
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tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
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oldskb->len - ip_hdrlen(oldskb) -
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(oth->doff << 2));
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tcph->ack = 1;
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}
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tcph->rst = 1;
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tcph->check = ~tcp_v4_check(sizeof(struct tcphdr), niph->saddr,
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niph->daddr, 0);
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nskb->ip_summed = CHECKSUM_PARTIAL;
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nskb->csum_start = (unsigned char *)tcph - nskb->head;
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nskb->csum_offset = offsetof(struct tcphdr, check);
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/* ip_route_me_harder expects skb->dst to be set */
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skb_dst_set_noref(nskb, skb_dst(oldskb));
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nskb->protocol = htons(ETH_P_IP);
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if (ip_route_me_harder(nskb, RTN_UNSPEC))
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goto free_nskb;
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niph->ttl = ip4_dst_hoplimit(skb_dst(nskb));
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/* "Never happens" */
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if (nskb->len > dst_mtu(skb_dst(nskb)))
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goto free_nskb;
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nf_ct_attach(nskb, oldskb);
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#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
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/* If we use ip_local_out for bridged traffic, the MAC source on
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* the RST will be ours, instead of the destination's. This confuses
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* some routers/firewalls, and they drop the packet. So we need to
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* build the eth header using the original destination's MAC as the
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* source, and send the RST packet directly.
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*/
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if (oldskb->nf_bridge) {
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struct ethhdr *oeth = eth_hdr(oldskb);
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nskb->dev = oldskb->nf_bridge->physindev;
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niph->tot_len = htons(nskb->len);
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ip_send_check(niph);
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if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol),
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oeth->h_source, oeth->h_dest, nskb->len) < 0)
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goto free_nskb;
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dev_queue_xmit(nskb);
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} else
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#endif
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ip_local_out(nskb);
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return;
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free_nskb:
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kfree_skb(nskb);
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}
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EXPORT_SYMBOL_GPL(nf_send_reset);
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@ -40,8 +40,13 @@ config NFT_CHAIN_ROUTE_IPV6
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fields such as the source, destination, flowlabel, hop-limit and
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the packet mark.
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config NF_REJECT_IPV6
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tristate "IPv6 packet rejection"
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default m if NETFILTER_ADVANCED=n
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config NFT_REJECT_IPV6
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depends on NF_TABLES_IPV6
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select NF_REJECT_IPV6
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default NFT_REJECT
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tristate
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@ -208,6 +213,7 @@ config IP6_NF_FILTER
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config IP6_NF_TARGET_REJECT
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tristate "REJECT target support"
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depends on IP6_NF_FILTER
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select NF_REJECT_IPV6
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default m if NETFILTER_ADVANCED=n
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help
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The REJECT target allows a filtering rule to specify that an ICMPv6
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@ -27,6 +27,9 @@ obj-$(CONFIG_NF_DEFRAG_IPV6) += nf_defrag_ipv6.o
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# logging
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obj-$(CONFIG_NF_LOG_IPV6) += nf_log_ipv6.o
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# reject
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obj-$(CONFIG_NF_REJECT_IPV6) += nf_reject_ipv6.o
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# nf_tables
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obj-$(CONFIG_NF_TABLES_IPV6) += nf_tables_ipv6.o
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obj-$(CONFIG_NFT_CHAIN_ROUTE_IPV6) += nft_chain_route_ipv6.o
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@ -0,0 +1,163 @@
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/* (C) 1999-2001 Paul `Rusty' Russell
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* (C) 2002-2004 Netfilter Core Team <coreteam@netfilter.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <net/ipv6.h>
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#include <net/ip6_route.h>
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#include <net/ip6_fib.h>
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#include <net/ip6_checksum.h>
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#include <linux/netfilter_ipv6.h>
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void nf_send_reset6(struct net *net, struct sk_buff *oldskb, int hook)
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{
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struct sk_buff *nskb;
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struct tcphdr otcph, *tcph;
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unsigned int otcplen, hh_len;
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int tcphoff, needs_ack;
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const struct ipv6hdr *oip6h = ipv6_hdr(oldskb);
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struct ipv6hdr *ip6h;
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#define DEFAULT_TOS_VALUE 0x0U
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const __u8 tclass = DEFAULT_TOS_VALUE;
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struct dst_entry *dst = NULL;
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u8 proto;
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__be16 frag_off;
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struct flowi6 fl6;
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if ((!(ipv6_addr_type(&oip6h->saddr) & IPV6_ADDR_UNICAST)) ||
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(!(ipv6_addr_type(&oip6h->daddr) & IPV6_ADDR_UNICAST))) {
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pr_debug("addr is not unicast.\n");
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return;
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}
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proto = oip6h->nexthdr;
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tcphoff = ipv6_skip_exthdr(oldskb, ((u8*)(oip6h+1) - oldskb->data), &proto, &frag_off);
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if ((tcphoff < 0) || (tcphoff > oldskb->len)) {
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pr_debug("Cannot get TCP header.\n");
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return;
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}
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otcplen = oldskb->len - tcphoff;
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/* IP header checks: fragment, too short. */
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if (proto != IPPROTO_TCP || otcplen < sizeof(struct tcphdr)) {
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pr_debug("proto(%d) != IPPROTO_TCP, "
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"or too short. otcplen = %d\n",
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proto, otcplen);
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return;
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}
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if (skb_copy_bits(oldskb, tcphoff, &otcph, sizeof(struct tcphdr)))
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BUG();
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/* No RST for RST. */
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if (otcph.rst) {
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pr_debug("RST is set\n");
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return;
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}
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/* Check checksum. */
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if (nf_ip6_checksum(oldskb, hook, tcphoff, IPPROTO_TCP)) {
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pr_debug("TCP checksum is invalid\n");
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return;
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}
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memset(&fl6, 0, sizeof(fl6));
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fl6.flowi6_proto = IPPROTO_TCP;
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fl6.saddr = oip6h->daddr;
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fl6.daddr = oip6h->saddr;
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fl6.fl6_sport = otcph.dest;
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fl6.fl6_dport = otcph.source;
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security_skb_classify_flow(oldskb, flowi6_to_flowi(&fl6));
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dst = ip6_route_output(net, NULL, &fl6);
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if (dst == NULL || dst->error) {
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dst_release(dst);
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return;
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}
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dst = xfrm_lookup(net, dst, flowi6_to_flowi(&fl6), NULL, 0);
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if (IS_ERR(dst))
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return;
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hh_len = (dst->dev->hard_header_len + 15)&~15;
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nskb = alloc_skb(hh_len + 15 + dst->header_len + sizeof(struct ipv6hdr)
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+ sizeof(struct tcphdr) + dst->trailer_len,
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GFP_ATOMIC);
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if (!nskb) {
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net_dbg_ratelimited("cannot alloc skb\n");
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dst_release(dst);
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return;
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}
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skb_dst_set(nskb, dst);
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skb_reserve(nskb, hh_len + dst->header_len);
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skb_put(nskb, sizeof(struct ipv6hdr));
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skb_reset_network_header(nskb);
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ip6h = ipv6_hdr(nskb);
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ip6_flow_hdr(ip6h, tclass, 0);
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ip6h->hop_limit = ip6_dst_hoplimit(dst);
|
||||
ip6h->nexthdr = IPPROTO_TCP;
|
||||
ip6h->saddr = oip6h->daddr;
|
||||
ip6h->daddr = oip6h->saddr;
|
||||
|
||||
skb_reset_transport_header(nskb);
|
||||
tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
|
||||
/* Truncate to length (no data) */
|
||||
tcph->doff = sizeof(struct tcphdr)/4;
|
||||
tcph->source = otcph.dest;
|
||||
tcph->dest = otcph.source;
|
||||
|
||||
if (otcph.ack) {
|
||||
needs_ack = 0;
|
||||
tcph->seq = otcph.ack_seq;
|
||||
tcph->ack_seq = 0;
|
||||
} else {
|
||||
needs_ack = 1;
|
||||
tcph->ack_seq = htonl(ntohl(otcph.seq) + otcph.syn + otcph.fin
|
||||
+ otcplen - (otcph.doff<<2));
|
||||
tcph->seq = 0;
|
||||
}
|
||||
|
||||
/* Reset flags */
|
||||
((u_int8_t *)tcph)[13] = 0;
|
||||
tcph->rst = 1;
|
||||
tcph->ack = needs_ack;
|
||||
tcph->window = 0;
|
||||
tcph->urg_ptr = 0;
|
||||
tcph->check = 0;
|
||||
|
||||
/* Adjust TCP checksum */
|
||||
tcph->check = csum_ipv6_magic(&ipv6_hdr(nskb)->saddr,
|
||||
&ipv6_hdr(nskb)->daddr,
|
||||
sizeof(struct tcphdr), IPPROTO_TCP,
|
||||
csum_partial(tcph,
|
||||
sizeof(struct tcphdr), 0));
|
||||
|
||||
nf_ct_attach(nskb, oldskb);
|
||||
|
||||
#if IS_ENABLED(CONFIG_BRIDGE_NETFILTER)
|
||||
/* If we use ip6_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 = oldskb->nf_bridge->physindev;
|
||||
nskb->protocol = htons(ETH_P_IPV6);
|
||||
ip6h->payload_len = htons(sizeof(struct tcphdr));
|
||||
if (dev_hard_header(nskb, nskb->dev, ntohs(nskb->protocol),
|
||||
oeth->h_source, oeth->h_dest, nskb->len) < 0)
|
||||
return;
|
||||
dev_queue_xmit(nskb);
|
||||
} else
|
||||
#endif
|
||||
ip6_local_out(nskb);
|
||||
}
|
||||
EXPORT_SYMBOL_GPL(nf_send_reset6);
|
||||
Loading…
Reference in New Issue