[PATCH 2.6.17] net/ipv6/udp.c: remove duplicate udp_get_port code
From: gerrit
Date: Wed Aug 16 2006 - 03:44:36 EST
UDPv4 and UDPv6 use an almost identical version of the get_port function,
which is unnecessary since the (long) code differs in only one if-statement.
By disentangling the if statement and adding v4/v6 checks appropriately, this
code duplication can be removed and further
* udp_port_rover can stay in net/ipv4/udp.c
* udp_lport_inuse can become static in net/ipv4/udp.c (only called by
udp_get_port
The text below discusses the re-arrangement of the if-statement. This is implemented
by enclosed patch (works both on stable and Torvalds' release). The patch also dispenses
with a goto statement whose jump label is referenced only once.
D i s c u s s i o n
The following compares the statements for udp_v{4,6}_get_port.
A) In udp_v4_get_port():
=========================
if (inet2->num == snum &&
sk2 != sk &&
!ipv6_only_sock(sk2) &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
(!inet2->rcv_saddr || !inet->rcv_saddr
|| inet2->rcv_saddr == inet->rcv_saddr) &&
(!sk2->sk_reuse || !sk->sk_reuse) )
goto fail;
This function is called from IPv4 context, hence sk->sk_family == PF_INET.
B) In udp_v6_get_port():
=========================
if (inet_sk(sk2)->num == snum &&
sk2 != sk &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
(!sk2->sk_reuse || !sk->sk_reuse) &&
ipv6_rcv_saddr_equal(sk, sk2) )
goto fail;
This function is called from IPv6 context, hence sk->sk_family == PF_INET6.
Common denominator:
===================
By re-ordering some of the last literals, both functions share the following
conjunction of conditions:
if (inet_sk(sk2)->num == snum && sk2 != sk &&
(!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
|| sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
(!sk2->sk_reuse || !sk->sk_reuse) )
To make the function applicable to both v4 and v6 contexts, a second if statement
is added, which branches according to sk's sk_family.
Signed-off-by: Gerrit Renker <gerrit@xxxxxxxxxxxxxx>
---
include/net/udp.h | 17 +----------
net/ipv4/udp.c | 57 ++++++++++++++++++++++++--------------
net/ipv6/udp.c | 79 +----------------------------------------------------
3 files changed, 38 insertions(+), 115 deletions(-)
diff --git a/include/net/udp.h b/include/net/udp.h
index 766fba1..69d4288 100644
--- a/include/net/udp.h
+++ b/include/net/udp.h
@@ -30,25 +30,9 @@ #include <linux/seq_file.h>
#define UDP_HTABLE_SIZE 128
-/* udp.c: This needs to be shared by v4 and v6 because the lookup
- * and hashing code needs to work with different AF's yet
- * the port space is shared.
- */
extern struct hlist_head udp_hash[UDP_HTABLE_SIZE];
extern rwlock_t udp_hash_lock;
-extern int udp_port_rover;
-
-static inline int udp_lport_inuse(u16 num)
-{
- struct sock *sk;
- struct hlist_node *node;
-
- sk_for_each(sk, node, &udp_hash[num & (UDP_HTABLE_SIZE - 1)])
- if (inet_sk(sk)->num == num)
- return 1;
- return 0;
-}
/* Note: this must match 'valbool' in sock_setsockopt */
#define UDP_CSUM_NOXMIT 1
@@ -63,6 +47,7 @@ extern struct proto udp_prot;
struct sk_buff;
+extern int udp_get_port(struct sock *sk, unsigned short snum);
extern void udp_err(struct sk_buff *, u32);
extern int udp_sendmsg(struct kiocb *iocb, struct sock *sk,
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 3f93292..eb3aa82 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -102,6 +102,7 @@ #include <net/protocol.h>
#include <linux/skbuff.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
+#include <net/addrconf.h>
#include <net/sock.h>
#include <net/udp.h>
#include <net/icmp.h>
@@ -119,10 +120,20 @@ DEFINE_SNMP_STAT(struct udp_mib, udp_sta
struct hlist_head udp_hash[UDP_HTABLE_SIZE];
DEFINE_RWLOCK(udp_hash_lock);
-/* Shared by v4/v6 udp. */
int udp_port_rover;
-static int udp_v4_get_port(struct sock *sk, unsigned short snum)
+static inline int udp_lport_inuse(u16 num)
+{
+ struct sock *sk;
+ struct hlist_node *node;
+
+ sk_for_each(sk, node, &udp_hash[num & (UDP_HTABLE_SIZE - 1)])
+ if (inet_sk(sk)->num == num)
+ return 1;
+ return 0;
+}
+
+int udp_get_port(struct sock *sk, unsigned short snum)
{
struct hlist_node *node;
struct sock *sk2;
@@ -151,11 +162,10 @@ static int udp_v4_get_port(struct sock *
}
size = 0;
sk_for_each(sk2, node, list)
- if (++size >= best_size_so_far)
- goto next;
- best_size_so_far = size;
- best = result;
- next:;
+ if (++size < best_size_so_far) {
+ best_size_so_far = size;
+ best = result;
+ }
}
result = best;
for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) {
@@ -175,24 +185,29 @@ gotit:
&udp_hash[snum & (UDP_HTABLE_SIZE - 1)]) {
struct inet_sock *inet2 = inet_sk(sk2);
- if (inet2->num == snum &&
- sk2 != sk &&
- !ipv6_only_sock(sk2) &&
+ if (inet2->num == snum &&
+ sk2 != sk &&
+ (!sk2->sk_reuse || !sk->sk_reuse) &&
(!sk2->sk_bound_dev_if ||
- !sk->sk_bound_dev_if ||
- sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
- (!inet2->rcv_saddr ||
- !inet->rcv_saddr ||
- inet2->rcv_saddr == inet->rcv_saddr) &&
- (!sk2->sk_reuse || !sk->sk_reuse))
- goto fail;
+ !sk->sk_bound_dev_if ||
+ sk2->sk_bound_dev_if == sk->sk_bound_dev_if) ) {
+ if (sk->sk_family == PF_INET &&
+ !ipv6_only_sock(sk2) &&
+ (!inet2->rcv_saddr ||
+ !inet->rcv_saddr ||
+ inet2->rcv_saddr == inet->rcv_saddr) )
+ goto fail;
+#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
+ else if(sk->sk_family == PF_INET6 &&
+ ipv6_rcv_saddr_equal(sk, sk2) )
+ goto fail;
+ }
+#endif
}
}
inet->num = snum;
if (sk_unhashed(sk)) {
- struct hlist_head *h = &udp_hash[snum & (UDP_HTABLE_SIZE - 1)];
-
- sk_add_node(sk, h);
+ sk_add_node(sk, &udp_hash[snum & (UDP_HTABLE_SIZE - 1)]);
sock_prot_inc_use(sk->sk_prot);
}
write_unlock_bh(&udp_hash_lock);
@@ -1385,7 +1400,7 @@ struct proto udp_prot = {
.backlog_rcv = udp_queue_rcv_skb,
.hash = udp_v4_hash,
.unhash = udp_v4_unhash,
- .get_port = udp_v4_get_port,
+ .get_port = udp_get_port,
.obj_size = sizeof(struct udp_sock),
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udp_setsockopt,
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 8d3432a..0d8b739 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -62,83 +62,6 @@ #include <linux/seq_file.h>
DEFINE_SNMP_STAT(struct udp_mib, udp_stats_in6) __read_mostly;
-/* Grrr, addr_type already calculated by caller, but I don't want
- * to add some silly "cookie" argument to this method just for that.
- */
-static int udp_v6_get_port(struct sock *sk, unsigned short snum)
-{
- struct sock *sk2;
- struct hlist_node *node;
-
- write_lock_bh(&udp_hash_lock);
- if (snum == 0) {
- int best_size_so_far, best, result, i;
-
- if (udp_port_rover > sysctl_local_port_range[1] ||
- udp_port_rover < sysctl_local_port_range[0])
- udp_port_rover = sysctl_local_port_range[0];
- best_size_so_far = 32767;
- best = result = udp_port_rover;
- for (i = 0; i < UDP_HTABLE_SIZE; i++, result++) {
- int size;
- struct hlist_head *list;
-
- list = &udp_hash[result & (UDP_HTABLE_SIZE - 1)];
- if (hlist_empty(list)) {
- if (result > sysctl_local_port_range[1])
- result = sysctl_local_port_range[0] +
- ((result - sysctl_local_port_range[0]) &
- (UDP_HTABLE_SIZE - 1));
- goto gotit;
- }
- size = 0;
- sk_for_each(sk2, node, list)
- if (++size >= best_size_so_far)
- goto next;
- best_size_so_far = size;
- best = result;
- next:;
- }
- result = best;
- for(i = 0; i < (1 << 16) / UDP_HTABLE_SIZE; i++, result += UDP_HTABLE_SIZE) {
- if (result > sysctl_local_port_range[1])
- result = sysctl_local_port_range[0]
- + ((result - sysctl_local_port_range[0]) &
- (UDP_HTABLE_SIZE - 1));
- if (!udp_lport_inuse(result))
- break;
- }
- if (i >= (1 << 16) / UDP_HTABLE_SIZE)
- goto fail;
-gotit:
- udp_port_rover = snum = result;
- } else {
- sk_for_each(sk2, node,
- &udp_hash[snum & (UDP_HTABLE_SIZE - 1)]) {
- if (inet_sk(sk2)->num == snum &&
- sk2 != sk &&
- (!sk2->sk_bound_dev_if ||
- !sk->sk_bound_dev_if ||
- sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
- (!sk2->sk_reuse || !sk->sk_reuse) &&
- ipv6_rcv_saddr_equal(sk, sk2))
- goto fail;
- }
- }
-
- inet_sk(sk)->num = snum;
- if (sk_unhashed(sk)) {
- sk_add_node(sk, &udp_hash[snum & (UDP_HTABLE_SIZE - 1)]);
- sock_prot_inc_use(sk->sk_prot);
- }
- write_unlock_bh(&udp_hash_lock);
- return 0;
-
-fail:
- write_unlock_bh(&udp_hash_lock);
- return 1;
-}
-
static void udp_v6_hash(struct sock *sk)
{
BUG();
@@ -1083,7 +1006,7 @@ struct proto udpv6_prot = {
.backlog_rcv = udpv6_queue_rcv_skb,
.hash = udp_v6_hash,
.unhash = udp_v6_unhash,
- .get_port = udp_v6_get_port,
+ .get_port = udp_get_port,
.obj_size = sizeof(struct udp6_sock),
#ifdef CONFIG_COMPAT
.compat_setsockopt = compat_udpv6_setsockopt,
-
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