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xt_ECHO: misc backports from ipt_REJECT and cosmetics

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This commit is contained in:
Jan Engelhardt
2011-09-24 23:16:58 +02:00
parent 3069c9a3a2
commit a508ec048c
1 changed files with 14 additions and 22 deletions
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36
extensions/xt_ECHO.c
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@@ -29,33 +29,33 @@ echo_tg4(struct sk_buff **poldskb, const struct xt_action_param *par)
struct udphdr *newudp, oldudp_buf;
struct iphdr *newip;
struct sk_buff *newskb;
unsigned int addr_type, data_len;
unsigned int data_len;
void *payload;
printk(KERN_INFO "dst_out=%p\n", skb_dst(*poldskb)->output);
/* This allows us to do the copy operation in fewer lines of code. */
if (skb_linearize(*poldskb) < 0)
return NF_DROP;
oldip = ip_hdr(oldskb);
oldudp = skb_header_pointer(oldskb, ip_hdrlen(oldskb),
sizeof(struct udphdr), &oldudp_buf);
oldudp = skb_header_pointer(oldskb, par->thoff,
sizeof(*oldudp), &oldudp_buf);
if (oldudp == NULL)
return NF_DROP;
if (ntohs(oldudp->len) <= sizeof(struct udphdr))
if (ntohs(oldudp->len) <= sizeof(*oldudp))
return NF_DROP;
newskb = alloc_skb(LL_MAX_HEADER + sizeof(struct iphdr) +
newskb = alloc_skb(LL_MAX_HEADER + sizeof(*newip) +
ntohs(oldudp->len), GFP_ATOMIC);
if (newskb == NULL)
return NF_DROP;
skb_reserve(newskb, LL_MAX_HEADER);
newskb->protocol = oldskb->protocol;
skb_reset_network_header(newskb);
newip = (void *)skb_put(newskb, sizeof(struct iphdr));
newip->version = 4;
newip->ihl = sizeof(struct iphdr) / 4;
newip = (void *)skb_put(newskb, sizeof(*newip));
newip->version = oldip->version;
newip->ihl = sizeof(*newip) / 4;
newip->tos = oldip->tos;
newip->id = 0;
newip->frag_off = htons(IP_DF);
@@ -64,30 +64,22 @@ echo_tg4(struct sk_buff **poldskb, const struct xt_action_param *par)
newip->saddr = oldip->daddr;
newip->daddr = oldip->saddr;
newudp = (void *)skb_put(newskb, sizeof(struct udphdr));
skb_reset_transport_header(newskb);
newudp = (void *)skb_put(newskb, sizeof(*newudp));
newudp->source = oldudp->dest;
newudp->dest = oldudp->source;
newudp->len = oldudp->len;
newudp->check = 0;
data_len = htons(oldudp->len) - sizeof(*oldudp);
payload = skb_header_pointer(oldskb, ip_hdrlen(oldskb) +
payload = skb_header_pointer(oldskb, par->thoff +
sizeof(*oldudp), data_len, NULL);
memcpy(skb_put(newskb, data_len), payload, data_len);
addr_type = RTN_UNSPEC;
#ifdef CONFIG_BRIDGE_NETFILTER
if (par->hooknum != NF_INET_FORWARD || (newskb->nf_bridge != NULL &&
newskb->nf_bridge->mask & BRNF_BRIDGED))
#else
if (par->hooknum != NF_INET_FORWARD)
#endif
addr_type = RTN_LOCAL;
/* ip_route_me_harder expects the skb's dst to be set */
skb_dst_set(newskb, dst_clone(skb_dst(oldskb)));
if (ip_route_me_harder(&newskb, addr_type) < 0)
if (ip_route_me_harder(&newskb, RTN_UNSPEC) != 0)
goto free_nskb;
newip->ttl = dst_metric(skb_dst(newskb), RTAX_HOPLIMIT);