1 #ifndef _IPV4_NF_REJECT_H
2 #define _IPV4_NF_REJECT_H
9 static inline void nf_send_unreach(struct sk_buff
*skb_in
, int code
)
11 icmp_send(skb_in
, ICMP_DEST_UNREACH
, code
, 0);
15 static void nf_send_reset(struct sk_buff
*oldskb
, int hook
)
18 const struct iphdr
*oiph
;
20 const struct tcphdr
*oth
;
21 struct tcphdr _otcph
, *tcph
;
23 /* IP header checks: fragment. */
24 if (ip_hdr(oldskb
)->frag_off
& htons(IP_OFFSET
))
27 oth
= skb_header_pointer(oldskb
, ip_hdrlen(oldskb
),
28 sizeof(_otcph
), &_otcph
);
36 if (skb_rtable(oldskb
)->rt_flags
& (RTCF_BROADCAST
| RTCF_MULTICAST
))
40 if (nf_ip_checksum(oldskb
, hook
, ip_hdrlen(oldskb
), IPPROTO_TCP
))
42 oiph
= ip_hdr(oldskb
);
44 nskb
= alloc_skb(sizeof(struct iphdr
) + sizeof(struct tcphdr
) +
45 LL_MAX_HEADER
, GFP_ATOMIC
);
49 skb_reserve(nskb
, LL_MAX_HEADER
);
51 skb_reset_network_header(nskb
);
52 niph
= (struct iphdr
*)skb_put(nskb
, sizeof(struct iphdr
));
54 niph
->ihl
= sizeof(struct iphdr
) / 4;
57 niph
->frag_off
= htons(IP_DF
);
58 niph
->protocol
= IPPROTO_TCP
;
60 niph
->saddr
= oiph
->daddr
;
61 niph
->daddr
= oiph
->saddr
;
63 skb_reset_transport_header(nskb
);
64 tcph
= (struct tcphdr
*)skb_put(nskb
, sizeof(struct tcphdr
));
65 memset(tcph
, 0, sizeof(*tcph
));
66 tcph
->source
= oth
->dest
;
67 tcph
->dest
= oth
->source
;
68 tcph
->doff
= sizeof(struct tcphdr
) / 4;
71 tcph
->seq
= oth
->ack_seq
;
73 tcph
->ack_seq
= htonl(ntohl(oth
->seq
) + oth
->syn
+ oth
->fin
+
74 oldskb
->len
- ip_hdrlen(oldskb
) -
80 tcph
->check
= ~tcp_v4_check(sizeof(struct tcphdr
), niph
->saddr
,
82 nskb
->ip_summed
= CHECKSUM_PARTIAL
;
83 nskb
->csum_start
= (unsigned char *)tcph
- nskb
->head
;
84 nskb
->csum_offset
= offsetof(struct tcphdr
, check
);
86 /* ip_route_me_harder expects skb->dst to be set */
87 skb_dst_set_noref(nskb
, skb_dst(oldskb
));
89 nskb
->protocol
= htons(ETH_P_IP
);
90 if (ip_route_me_harder(nskb
, RTN_UNSPEC
))
93 niph
->ttl
= ip4_dst_hoplimit(skb_dst(nskb
));
96 if (nskb
->len
> dst_mtu(skb_dst(nskb
)))
99 nf_ct_attach(nskb
, oldskb
);
101 #ifdef CONFIG_BRIDGE_NETFILTER
102 /* If we use ip_local_out for bridged traffic, the MAC source on
103 * the RST will be ours, instead of the destination's. This confuses
104 * some routers/firewalls, and they drop the packet. So we need to
105 * build the eth header using the original destination's MAC as the
106 * source, and send the RST packet directly.
108 if (oldskb
->nf_bridge
) {
109 struct ethhdr
*oeth
= eth_hdr(oldskb
);
110 nskb
->dev
= oldskb
->nf_bridge
->physindev
;
111 niph
->tot_len
= htons(nskb
->len
);
113 if (dev_hard_header(nskb
, nskb
->dev
, ntohs(nskb
->protocol
),
114 oeth
->h_source
, oeth
->h_dest
, nskb
->len
) < 0)
116 dev_queue_xmit(nskb
);
128 #endif /* _IPV4_NF_REJECT_H */
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