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[DCCP]: calling dccp_v{4,6}_reqsk_send_ack is a BUG 

This patch removes two functions, the send_ack functions of request_sock,
which are not called/used by the DCCP code. It is correct that these
functions are not called, below is a justification why calling these
functions (on a passive socket in the LISTEN/RESPOND state) would mean
a DCCP protocol violation.

A) Background: using request_sock in TCP:
This commit is contained in:
Gerrit Renker 2006-11-10 12:32:01 -02:00 committed by David S. Miller
parent f6484f7c7a
commit 8a73cd09d9
4 changed files with 14 additions and 103 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
net/dccp/dccp.h
View File

@ -131,6 +131,8 @@ extern int dccp_retransmit_skb(struct sock *sk, struct sk_buff *skb);
extern void dccp_send_ack(struct sock *sk);
extern void dccp_send_delayed_ack(struct sock *sk);
extern void dccp_reqsk_send_ack(struct sk_buff *sk, struct request_sock *rsk);
extern void dccp_send_sync(struct sock *sk, const u64 seq,
const enum dccp_pkt_type pkt_type);

48
net/dccp/ipv4.c
View File

@ -193,52 +193,6 @@ static inline void dccp_do_pmtu_discovery(struct sock *sk,
} /* else let the usual retransmit timer handle it */
}
static void dccp_v4_reqsk_send_ack(struct sk_buff *rxskb,
struct request_sock *req)
{
int err;
struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
const u32 dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_ack_bits);
struct sk_buff *skb;
if (((struct rtable *)rxskb->dst)->rt_type != RTN_LOCAL)
return;
skb = alloc_skb(dccp_v4_ctl_socket->sk->sk_prot->max_header, GFP_ATOMIC);
if (skb == NULL)
return;
/* Reserve space for headers. */
skb_reserve(skb, dccp_v4_ctl_socket->sk->sk_prot->max_header);
skb->dst = dst_clone(rxskb->dst);
dh = dccp_zeroed_hdr(skb, dccp_hdr_ack_len);
/* Build DCCP header and checksum it. */
dh->dccph_type = DCCP_PKT_ACK;
dh->dccph_sport = rxdh->dccph_dport;
dh->dccph_dport = rxdh->dccph_sport;
dh->dccph_doff = dccp_hdr_ack_len / 4;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
DCCP_SKB_CB(rxskb)->dccpd_seq);
bh_lock_sock(dccp_v4_ctl_socket->sk);
err = ip_build_and_send_pkt(skb, dccp_v4_ctl_socket->sk,
rxskb->nh.iph->daddr,
rxskb->nh.iph->saddr, NULL);
bh_unlock_sock(dccp_v4_ctl_socket->sk);
if (err == NET_XMIT_CN || err == 0) {
DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
DCCP_INC_STATS_BH(DCCP_MIB_OUTRSTS);
}
}
static int dccp_v4_send_response(struct sock *sk, struct request_sock *req,
struct dst_entry *dst)
{
@ -1014,7 +968,7 @@ static struct request_sock_ops dccp_request_sock_ops __read_mostly = {
.family = PF_INET,
.obj_size = sizeof(struct dccp_request_sock),
.rtx_syn_ack = dccp_v4_send_response,
.send_ack = dccp_v4_reqsk_send_ack,
.send_ack = dccp_reqsk_send_ack,
.destructor = dccp_v4_reqsk_destructor,
.send_reset = dccp_v4_ctl_send_reset,
};

57
net/dccp/ipv6.c
View File

@ -37,8 +37,6 @@
static struct socket *dccp_v6_ctl_socket;
static void dccp_v6_ctl_send_reset(struct sk_buff *skb);
static void dccp_v6_reqsk_send_ack(struct sk_buff *skb,
struct request_sock *req);
static void dccp_v6_send_check(struct sock *sk, int len, struct sk_buff *skb);
static int dccp_v6_do_rcv(struct sock *sk, struct sk_buff *skb);
@ -493,7 +491,7 @@ static struct request_sock_ops dccp6_request_sock_ops = {
.family = AF_INET6,
.obj_size = sizeof(struct dccp6_request_sock),
.rtx_syn_ack = dccp_v6_send_response,
.send_ack = dccp_v6_reqsk_send_ack,
.send_ack = dccp_reqsk_send_ack,
.destructor = dccp_v6_reqsk_destructor,
.send_reset = dccp_v6_ctl_send_reset,
};
@ -582,59 +580,6 @@ static void dccp_v6_ctl_send_reset(struct sk_buff *rxskb)
kfree_skb(skb);
}
static void dccp_v6_reqsk_send_ack(struct sk_buff *rxskb,
struct request_sock *req)
{
struct flowi fl;
struct dccp_hdr *rxdh = dccp_hdr(rxskb), *dh;
const u32 dccp_hdr_ack_len = sizeof(struct dccp_hdr) +
sizeof(struct dccp_hdr_ext) +
sizeof(struct dccp_hdr_ack_bits);
struct sk_buff *skb;
skb = alloc_skb(dccp_v6_ctl_socket->sk->sk_prot->max_header,
GFP_ATOMIC);
if (skb == NULL)
return;
skb_reserve(skb, dccp_v6_ctl_socket->sk->sk_prot->max_header);
dh = dccp_zeroed_hdr(skb, dccp_hdr_ack_len);
/* Build DCCP header and checksum it. */
dh->dccph_type = DCCP_PKT_ACK;
dh->dccph_sport = rxdh->dccph_dport;
dh->dccph_dport = rxdh->dccph_sport;
dh->dccph_doff = dccp_hdr_ack_len / 4;
dh->dccph_x = 1;
dccp_hdr_set_seq(dh, DCCP_SKB_CB(rxskb)->dccpd_ack_seq);
dccp_hdr_set_ack(dccp_hdr_ack_bits(skb),
DCCP_SKB_CB(rxskb)->dccpd_seq);
memset(&fl, 0, sizeof(fl));
ipv6_addr_copy(&fl.fl6_dst, &rxskb->nh.ipv6h->saddr);
ipv6_addr_copy(&fl.fl6_src, &rxskb->nh.ipv6h->daddr);
/* FIXME: calculate checksum, IPv4 also should... */
fl.proto = IPPROTO_DCCP;
fl.oif = inet6_iif(rxskb);
fl.fl_ip_dport = dh->dccph_dport;
fl.fl_ip_sport = dh->dccph_sport;
security_req_classify_flow(req, &fl);
if (!ip6_dst_lookup(NULL, &skb->dst, &fl)) {
if (xfrm_lookup(&skb->dst, &fl, NULL, 0) >= 0) {
ip6_xmit(dccp_v6_ctl_socket->sk, skb, &fl, NULL, 0);
DCCP_INC_STATS_BH(DCCP_MIB_OUTSEGS);
return;
}
}
kfree_skb(skb);
}
static struct sock *dccp_v6_hnd_req(struct sock *sk,struct sk_buff *skb)
{
const struct dccp_hdr *dh = dccp_hdr(skb);

10
net/dccp/minisocks.c
View File

@ -11,6 +11,7 @@
*/
#include <linux/dccp.h>
#include <linux/kernel.h>
#include <linux/skbuff.h>
#include <linux/timer.h>
@ -283,3 +284,12 @@ int dccp_child_process(struct sock *parent, struct sock *child,
}
EXPORT_SYMBOL_GPL(dccp_child_process);
void dccp_reqsk_send_ack(struct sk_buff *skb, struct request_sock *rsk)
{
pr_info(KERN_WARNING "DCCP: ACK packets are never sent in "
"LISTEN/RESPOND state\n");
dump_stack();
}
EXPORT_SYMBOL_GPL(dccp_reqsk_send_ack);