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[TCP]: Add IPv6 support to TCP SYN cookies

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Updated to incorporate Eric's suggestion of using a per cpu buffer
rather than allocating on the stack.  Just a two line change, but will
resend in it's entirety.

Signed-off-by: Glenn Griffin <ggriffin.kernel@gmail.com>
Signed-off-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
This commit is contained in:
Glenn Griffin
2008-02-07 21:49:26 -08:00
committed by YOSHIFUJI Hideaki
parent 11baab7ac3
commit c6aefafb7e
8 changed files with 338 additions and 26 deletions
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77
net/ipv6/tcp_ipv6.c
View File

@ -512,6 +512,20 @@ done:
return err;
}
static inline void syn_flood_warning(struct sk_buff *skb)
{
#ifdef CONFIG_SYN_COOKIES
if (sysctl_tcp_syncookies)
printk(KERN_INFO
"TCPv6: Possible SYN flooding on port %d. "
"Sending cookies.\n", ntohs(tcp_hdr(skb)->dest));
else
#endif
printk(KERN_INFO
"TCPv6: Possible SYN flooding on port %d. "
"Dropping request.\n", ntohs(tcp_hdr(skb)->dest));
}
static void tcp_v6_reqsk_destructor(struct request_sock *req)
{
if (inet6_rsk(req)->pktopts)
@ -915,7 +929,7 @@ done_opts:
}
#endif
static struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
struct request_sock_ops tcp6_request_sock_ops __read_mostly = {
.family = AF_INET6,
.obj_size = sizeof(struct tcp6_request_sock),
.rtx_syn_ack = tcp_v6_send_synack,
@ -1213,9 +1227,9 @@ static struct sock *tcp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
return NULL;
}
#if 0 /*def CONFIG_SYN_COOKIES*/
#ifdef CONFIG_SYN_COOKIES
if (!th->rst && !th->syn && th->ack)
sk = cookie_v6_check(sk, skb, &(IPCB(skb)->opt));
sk = cookie_v6_check(sk, skb);
#endif
return sk;
}
@ -1231,6 +1245,11 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
struct tcp_sock *tp = tcp_sk(sk);
struct request_sock *req = NULL;
__u32 isn = TCP_SKB_CB(skb)->when;
#ifdef CONFIG_SYN_COOKIES
int want_cookie = 0;
#else
#define want_cookie 0
#endif
if (skb->protocol == htons(ETH_P_IP))
return tcp_v4_conn_request(sk, skb);
@ -1238,12 +1257,14 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
if (!ipv6_unicast_destination(skb))
goto drop;
/*
* There are no SYN attacks on IPv6, yet...
*/
if (inet_csk_reqsk_queue_is_full(sk) && !isn) {
if (net_ratelimit())
printk(KERN_INFO "TCPv6: dropping request, synflood is possible\n");
syn_flood_warning(skb);
#ifdef CONFIG_SYN_COOKIES
if (sysctl_tcp_syncookies)
want_cookie = 1;
else
#endif
goto drop;
}
@ -1264,29 +1285,39 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
tcp_parse_options(skb, &tmp_opt, 0);
if (want_cookie) {
tcp_clear_options(&tmp_opt);
tmp_opt.saw_tstamp = 0;
}
tmp_opt.tstamp_ok = tmp_opt.saw_tstamp;
tcp_openreq_init(req, &tmp_opt, skb);
treq = inet6_rsk(req);
ipv6_addr_copy(&treq->rmt_addr, &ipv6_hdr(skb)->saddr);
ipv6_addr_copy(&treq->loc_addr, &ipv6_hdr(skb)->daddr);
TCP_ECN_create_request(req, tcp_hdr(skb));
treq->pktopts = NULL;
if (ipv6_opt_accepted(sk, skb) ||
np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
atomic_inc(&skb->users);
treq->pktopts = skb;
}
treq->iif = sk->sk_bound_dev_if;
if (!want_cookie)
TCP_ECN_create_request(req, tcp_hdr(skb));
/* So that link locals have meaning */
if (!sk->sk_bound_dev_if &&
ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
treq->iif = inet6_iif(skb);
if (want_cookie) {
isn = cookie_v6_init_sequence(sk, skb, &req->mss);
} else if (!isn) {
if (ipv6_opt_accepted(sk, skb) ||
np->rxopt.bits.rxinfo || np->rxopt.bits.rxoinfo ||
np->rxopt.bits.rxhlim || np->rxopt.bits.rxohlim) {
atomic_inc(&skb->users);
treq->pktopts = skb;
}
treq->iif = sk->sk_bound_dev_if;
/* So that link locals have meaning */
if (!sk->sk_bound_dev_if &&
ipv6_addr_type(&treq->rmt_addr) & IPV6_ADDR_LINKLOCAL)
treq->iif = inet6_iif(skb);
if (isn == 0)
isn = tcp_v6_init_sequence(skb);
}
tcp_rsk(req)->snt_isn = isn;
@ -1295,8 +1326,10 @@ static int tcp_v6_conn_request(struct sock *sk, struct sk_buff *skb)
if (tcp_v6_send_synack(sk, req))
goto drop;
inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
return 0;
if (!want_cookie) {
inet6_csk_reqsk_queue_hash_add(sk, req, TCP_TIMEOUT_INIT);
return 0;
}
drop:
if (req)