MODULE_LICENSE("GPL");
MODULE_AUTHOR("Netfilter Core Team <coreteam@netfilter.org>");
-MODULE_DESCRIPTION("iptables REJECT target module");
+MODULE_DESCRIPTION("Xtables: packet \"rejection\" target for IPv4");
/* Send RST reply */
static void send_reset(struct sk_buff *oldskb, int hook)
{
struct sk_buff *nskb;
+ const struct iphdr *oiph;
struct iphdr *niph;
- struct tcphdr _otcph, *oth, *tcph;
- __be16 tmp_port;
- __be32 tmp_addr;
- int needs_ack;
+ const struct tcphdr *oth;
+ struct tcphdr _otcph, *tcph;
unsigned int addr_type;
/* IP header checks: fragment. */
/* Check checksum */
if (nf_ip_checksum(oldskb, hook, ip_hdrlen(oldskb), IPPROTO_TCP))
return;
+ oiph = ip_hdr(oldskb);
- /* We need a linear, writeable skb. We also need to expand
- headroom in case hh_len of incoming interface < hh_len of
- outgoing interface */
- nskb = skb_copy_expand(oldskb, LL_MAX_HEADER, skb_tailroom(oldskb),
- GFP_ATOMIC);
+ nskb = alloc_skb(sizeof(struct iphdr) + sizeof(struct tcphdr) +
+ LL_MAX_HEADER, GFP_ATOMIC);
if (!nskb)
return;
- /* This packet will not be the same as the other: clear nf fields */
- nf_reset(nskb);
- nskb->mark = 0;
- skb_init_secmark(nskb);
-
- skb_shinfo(nskb)->gso_size = 0;
- skb_shinfo(nskb)->gso_segs = 0;
- skb_shinfo(nskb)->gso_type = 0;
-
- tcph = (struct tcphdr *)(skb_network_header(nskb) + ip_hdrlen(nskb));
-
- /* Swap source and dest */
- niph = ip_hdr(nskb);
- tmp_addr = niph->saddr;
- niph->saddr = niph->daddr;
- niph->daddr = tmp_addr;
- tmp_port = tcph->source;
- tcph->source = tcph->dest;
- tcph->dest = tmp_port;
-
- /* Truncate to length (no data) */
- tcph->doff = sizeof(struct tcphdr)/4;
- skb_trim(nskb, ip_hdrlen(nskb) + sizeof(struct tcphdr));
- niph->tot_len = htons(nskb->len);
-
- if (tcph->ack) {
- needs_ack = 0;
+ skb_reserve(nskb, LL_MAX_HEADER);
+
+ skb_reset_network_header(nskb);
+ niph = (struct iphdr *)skb_put(nskb, sizeof(struct iphdr));
+ niph->version = 4;
+ niph->ihl = sizeof(struct iphdr) / 4;
+ niph->tos = 0;
+ niph->id = 0;
+ niph->frag_off = htons(IP_DF);
+ niph->protocol = IPPROTO_TCP;
+ niph->check = 0;
+ niph->saddr = oiph->daddr;
+ niph->daddr = oiph->saddr;
+
+ tcph = (struct tcphdr *)skb_put(nskb, sizeof(struct tcphdr));
+ memset(tcph, 0, sizeof(*tcph));
+ tcph->source = oth->dest;
+ tcph->dest = oth->source;
+ tcph->doff = sizeof(struct tcphdr) / 4;
+
+ if (oth->ack)
tcph->seq = oth->ack_seq;
- tcph->ack_seq = 0;
- } else {
- needs_ack = 1;
+ else {
tcph->ack_seq = htonl(ntohl(oth->seq) + oth->syn + oth->fin +
oldskb->len - ip_hdrlen(oldskb) -
(oth->doff << 2));
- tcph->seq = 0;
+ tcph->ack = 1;
}
- /* Reset flags */
- ((u_int8_t *)tcph)[13] = 0;
- tcph->rst = 1;
- tcph->ack = needs_ack;
-
- tcph->window = 0;
- tcph->urg_ptr = 0;
-
- /* Adjust TCP checksum */
- tcph->check = 0;
- tcph->check = tcp_v4_check(sizeof(struct tcphdr),
- niph->saddr, niph->daddr,
- csum_partial(tcph,
- sizeof(struct tcphdr), 0));
-
- /* Set DF, id = 0 */
- niph->frag_off = htons(IP_DF);
- niph->id = 0;
+ tcph->rst = 1;
+ tcph->check = tcp_v4_check(sizeof(struct tcphdr),
+ niph->saddr, niph->daddr,
+ csum_partial(tcph,
+ sizeof(struct tcphdr), 0));
addr_type = RTN_UNSPEC;
- if (hook != NF_IP_FORWARD
+ if (hook != NF_INET_FORWARD
#ifdef CONFIG_BRIDGE_NETFILTER
|| (nskb->nf_bridge && nskb->nf_bridge->mask & BRNF_BRIDGED)
#endif
)
addr_type = RTN_LOCAL;
+ /* ip_route_me_harder expects skb->dst to be set */
+ dst_hold(oldskb->dst);
+ nskb->dst = oldskb->dst;
+
if (ip_route_me_harder(nskb, addr_type))
goto free_nskb;
+ niph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
nskb->ip_summed = CHECKSUM_NONE;
- /* Adjust IP TTL */
- niph->ttl = dst_metric(nskb->dst, RTAX_HOPLIMIT);
-
- /* Adjust IP checksum */
- niph->check = 0;
- niph->check = ip_fast_csum(skb_network_header(nskb), niph->ihl);
-
/* "Never happens" */
if (nskb->len > dst_mtu(nskb->dst))
goto free_nskb;
nf_ct_attach(nskb, oldskb);
- NF_HOOK(PF_INET, NF_IP_LOCAL_OUT, nskb, NULL, nskb->dst->dev,
- dst_output);
+ ip_local_out(nskb);
return;
free_nskb:
icmp_send(skb_in, ICMP_DEST_UNREACH, code, 0);
}
-static unsigned int reject(struct sk_buff *skb,
- const struct net_device *in,
- const struct net_device *out,
- unsigned int hooknum,
- const struct xt_target *target,
- const void *targinfo)
+static unsigned int
+reject_tg(struct sk_buff *skb, const struct net_device *in,
+ const struct net_device *out, unsigned int hooknum,
+ const struct xt_target *target, const void *targinfo)
{
const struct ipt_reject_info *reject = targinfo;
- /* Our naive response construction doesn't deal with IP
- options, and probably shouldn't try. */
- if (ip_hdrlen(skb) != sizeof(struct iphdr))
- return NF_DROP;
-
/* WARNING: This code causes reentry within iptables.
This means that the iptables jump stack is now crap. We
must return an absolute verdict. --RR */
return NF_DROP;
}
-static bool check(const char *tablename,
- const void *e_void,
- const struct xt_target *target,
- void *targinfo,
- unsigned int hook_mask)
+static bool
+reject_tg_check(const char *tablename, const void *e_void,
+ const struct xt_target *target, void *targinfo,
+ unsigned int hook_mask)
{
const struct ipt_reject_info *rejinfo = targinfo;
const struct ipt_entry *e = e_void;
return true;
}
-static struct xt_target ipt_reject_reg __read_mostly = {
+static struct xt_target reject_tg_reg __read_mostly = {
.name = "REJECT",
.family = AF_INET,
- .target = reject,
+ .target = reject_tg,
.targetsize = sizeof(struct ipt_reject_info),
.table = "filter",
- .hooks = (1 << NF_IP_LOCAL_IN) | (1 << NF_IP_FORWARD) |
- (1 << NF_IP_LOCAL_OUT),
- .checkentry = check,
+ .hooks = (1 << NF_INET_LOCAL_IN) | (1 << NF_INET_FORWARD) |
+ (1 << NF_INET_LOCAL_OUT),
+ .checkentry = reject_tg_check,
.me = THIS_MODULE,
};
-static int __init ipt_reject_init(void)
+static int __init reject_tg_init(void)
{
- return xt_register_target(&ipt_reject_reg);
+ return xt_register_target(&reject_tg_reg);
}
-static void __exit ipt_reject_fini(void)
+static void __exit reject_tg_exit(void)
{
- xt_unregister_target(&ipt_reject_reg);
+ xt_unregister_target(&reject_tg_reg);
}
-module_init(ipt_reject_init);
-module_exit(ipt_reject_fini);
+module_init(reject_tg_init);
+module_exit(reject_tg_exit);
projects / linux-2.6-omap-h63xx.git / blobdiff