[UDP]: Revert 2-pass hashing changes.

This reverts changesets:

6aaf47fa48d3c44280810b1b470261d340e4ed87
b7b5f487ab39bc10ed0694af35651a03d9cb97ff
de34ed91c4ffa4727964a832c46e624dd1495cf5
fc038410b4b1643766f8033f4940bcdb1dace633

There are still some correctness issues recently
discovered which do not have a known fix that doesn't
involve doing a full hash table scan on port bind.

So revert for now.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 68 insertions, 173 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index 5da703e699da..facb7e29304e 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -114,36 +114,14 @@ DEFINE_RWLOCK(udp_hash_lock);
 
 static int udp_port_rover;
 
-/*
- * Note about this hash function :
- * Typical use is probably daddr = 0, only dport is going to vary hash
- */
-static inline unsigned int udp_hash_port(__u16 port)
-{
-        return port;
-}
-
-static inline int __udp_lib_port_inuse(unsigned int hash, int port,
-                                       const struct sock *this_sk,
-                                       struct hlist_head udptable[],
-                                       const struct udp_get_port_ops *ops)
+static inline int __udp_lib_lport_inuse(__u16 num, struct hlist_head udptable[])
 {
         struct sock *sk;
         struct hlist_node *node;
-        struct inet_sock *inet;
 
-        sk_for_each(sk, node, &udptable[hash & (UDP_HTABLE_SIZE - 1)]) {
-                if (sk->sk_hash != hash)
-                        continue;
-                inet = inet_sk(sk);
-                if (inet->num != port)
-                        continue;
-                if (this_sk) {
-                        if (ops->saddr_cmp(sk, this_sk))
-                                return 1;
-                } else if (ops->saddr_any(sk))
+        sk_for_each(sk, node, &udptable[num & (UDP_HTABLE_SIZE - 1)])
+                if (sk->sk_hash == num)
                         return 1;
-        }
         return 0;
 }
 
@@ -154,16 +132,16 @@ static inline int __udp_lib_port_inuse(unsigned int hash, int port,
  *  @snum:        port number to look up
  *  @udptable:    hash list table, must be of UDP_HTABLE_SIZE
  *  @port_rover:  pointer to record of last unallocated port
- *  @ops:         AF-dependent address operations
+ *  @saddr_comp:  AF-dependent comparison of bound local IP addresses
  */
 int __udp_lib_get_port(struct sock *sk, unsigned short snum,
                        struct hlist_head udptable[], int *port_rover,
-                       const struct udp_get_port_ops *ops)
+                       int (*saddr_comp)(const struct sock *sk1,
+                                         const struct sock *sk2 )    )
 {
         struct hlist_node *node;
         struct hlist_head *head;
         struct sock *sk2;
-        unsigned int hash;
         int    error = 1;
 
         write_lock_bh(&udp_hash_lock);
@@ -178,8 +156,7 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
                 for (i = 0; i < UDP_HTABLE_SIZE; i++, result++) {
                         int size;
 
-                        hash = ops->hash_port_and_rcv_saddr(result, sk);
-                        head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
+                        head = &udptable[result & (UDP_HTABLE_SIZE - 1)];
                         if (hlist_empty(head)) {
                                 if (result > sysctl_local_port_range[1])
                                         result = sysctl_local_port_range[0] +
@@ -204,16 +181,7 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
                                 result = sysctl_local_port_range[0]
                                         + ((result - sysctl_local_port_range[0]) &
                                            (UDP_HTABLE_SIZE - 1));
-                        hash = udp_hash_port(result);
-                        if (__udp_lib_port_inuse(hash, result,
-                                                 NULL, udptable, ops))
-                                continue;
-                        if (ops->saddr_any(sk))
-                                break;
-
-                        hash = ops->hash_port_and_rcv_saddr(result, sk);
-                        if (! __udp_lib_port_inuse(hash, result,
-                                                   sk, udptable, ops))
+                        if (! __udp_lib_lport_inuse(result, udptable))
                                 break;
                 }
                 if (i >= (1 << 16) / UDP_HTABLE_SIZE)
@@ -221,40 +189,21 @@ int __udp_lib_get_port(struct sock *sk, unsigned short snum,
 gotit:
                 *port_rover = snum = result;
         } else {
-                hash = udp_hash_port(snum);
-                head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
+                head = &udptable[snum & (UDP_HTABLE_SIZE - 1)];
 
                 sk_for_each(sk2, node, head)
-                        if (sk2->sk_hash == hash &&
-                            sk2 != sk &&
-                            inet_sk(sk2)->num == snum &&
-                            (!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) &&
-                            ops->saddr_cmp(sk, sk2))
+                        if (sk2->sk_hash == 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) &&
+                            (*saddr_comp)(sk, sk2)                             )
                                 goto fail;
-
-                if (!ops->saddr_any(sk)) {
-                        hash = ops->hash_port_and_rcv_saddr(snum, sk);
-                        head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
-
-                        sk_for_each(sk2, node, head)
-                                if (sk2->sk_hash == hash &&
-                                    sk2 != sk &&
-                                    inet_sk(sk2)->num == snum &&
-                                    (!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) &&
-                                    ops->saddr_cmp(sk, sk2))
-                                        goto fail;
-                }
         }
         inet_sk(sk)->num = snum;
-        sk->sk_hash = hash;
+        sk->sk_hash = snum;
         if (sk_unhashed(sk)) {
-                head = &udptable[hash & (UDP_HTABLE_SIZE - 1)];
+                head = &udptable[snum & (UDP_HTABLE_SIZE - 1)];
                 sk_add_node(sk, head);
                 sock_prot_inc_use(sk->sk_prot);
         }
@@ -265,12 +214,12 @@ fail:
 }
 
 int udp_get_port(struct sock *sk, unsigned short snum,
-                 const struct udp_get_port_ops *ops)
+                        int (*scmp)(const struct sock *, const struct sock *))
 {
-        return  __udp_lib_get_port(sk, snum, udp_hash, &udp_port_rover, ops);
+        return  __udp_lib_get_port(sk, snum, udp_hash, &udp_port_rover, scmp);
 }
 
-static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
+int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
 {
         struct inet_sock *inet1 = inet_sk(sk1), *inet2 = inet_sk(sk2);
 
@@ -279,33 +228,9 @@ static int ipv4_rcv_saddr_equal(const struct sock *sk1, const struct sock *sk2)
                    inet1->rcv_saddr == inet2->rcv_saddr      ));
 }
 
-static int ipv4_rcv_saddr_any(const struct sock *sk)
-{
-        return !inet_sk(sk)->rcv_saddr;
-}
-
-static inline unsigned int ipv4_hash_port_and_addr(__u16 port, __be32 addr)
-{
-        addr ^= addr >> 16;
-        addr ^= addr >> 8;
-        return port ^ addr;
-}
-
-static unsigned int ipv4_hash_port_and_rcv_saddr(__u16 port,
-                                                 const struct sock *sk)
-{
-        return ipv4_hash_port_and_addr(port, inet_sk(sk)->rcv_saddr);
-}
-
-const struct udp_get_port_ops udp_ipv4_ops = {
-        .saddr_cmp = ipv4_rcv_saddr_equal,
-        .saddr_any = ipv4_rcv_saddr_any,
-        .hash_port_and_rcv_saddr = ipv4_hash_port_and_rcv_saddr,
-};
-
 static inline int udp_v4_get_port(struct sock *sk, unsigned short snum)
 {
-        return udp_get_port(sk, snum, &udp_ipv4_ops);
+        return udp_get_port(sk, snum, ipv4_rcv_saddr_equal);
 }
 
 /* UDP is nearly always wildcards out the wazoo, it makes no sense to try
@@ -317,77 +242,63 @@ static struct sock *__udp4_lib_lookup(__be32 saddr, __be16 sport,
 {
         struct sock *sk, *result = NULL;
         struct hlist_node *node;
-        unsigned int hash, hashwild;
-        int score, best = -1, hport = ntohs(dport);
-
-        hash = ipv4_hash_port_and_addr(hport, daddr);
-        hashwild = udp_hash_port(hport);
+        unsigned short hnum = ntohs(dport);
+        int badness = -1;
 
         read_lock(&udp_hash_lock);
-
-lookup:
-
-        sk_for_each(sk, node, &udptable[hash & (UDP_HTABLE_SIZE - 1)]) {
+        sk_for_each(sk, node, &udptable[hnum & (UDP_HTABLE_SIZE - 1)]) {
                 struct inet_sock *inet = inet_sk(sk);
 
-                if (sk->sk_hash != hash || ipv6_only_sock(sk) ||
-                        inet->num != hport)
-                        continue;
-
-                score = (sk->sk_family == PF_INET ? 1 : 0);
-                if (inet->rcv_saddr) {
-                        if (inet->rcv_saddr != daddr)
-                                continue;
-                        score+=2;
-                }
-                if (inet->daddr) {
-                        if (inet->daddr != saddr)
-                                continue;
-                        score+=2;
-                }
-                if (inet->dport) {
-                        if (inet->dport != sport)
-                                continue;
-                        score+=2;
-                }
-                if (sk->sk_bound_dev_if) {
-                        if (sk->sk_bound_dev_if != dif)
-                                continue;
-                        score+=2;
-                }
-                if (score == 9) {
-                        result = sk;
-                        goto found;
-                } else if (score > best) {
-                        result = sk;
-                        best = score;
+                if (sk->sk_hash == hnum && !ipv6_only_sock(sk)) {
+                        int score = (sk->sk_family == PF_INET ? 1 : 0);
+                        if (inet->rcv_saddr) {
+                                if (inet->rcv_saddr != daddr)
+                                        continue;
+                                score+=2;
+                        }
+                        if (inet->daddr) {
+                                if (inet->daddr != saddr)
+                                        continue;
+                                score+=2;
+                        }
+                        if (inet->dport) {
+                                if (inet->dport != sport)
+                                        continue;
+                                score+=2;
+                        }
+                        if (sk->sk_bound_dev_if) {
+                                if (sk->sk_bound_dev_if != dif)
+                                        continue;
+                                score+=2;
+                        }
+                        if (score == 9) {
+                                result = sk;
+                                break;
+                        } else if (score > badness) {
+                                result = sk;
+                                badness = score;
+                        }
                 }
         }
-
-        if (hash != hashwild) {
-                hash = hashwild;
-                goto lookup;
-        }
-found:
         if (result)
                 sock_hold(result);
         read_unlock(&udp_hash_lock);
         return result;
 }
 
-static inline struct sock *udp_v4_mcast_next(struct sock *sk, unsigned int hnum,
-                                             int hport, __be32 loc_addr,
+static inline struct sock *udp_v4_mcast_next(struct sock *sk,
+                                             __be16 loc_port, __be32 loc_addr,
                                              __be16 rmt_port, __be32 rmt_addr,
                                              int dif)
 {
         struct hlist_node *node;
         struct sock *s = sk;
+        unsigned short hnum = ntohs(loc_port);
 
         sk_for_each_from(s, node) {
                 struct inet_sock *inet = inet_sk(s);
 
                 if (s->sk_hash != hnum                                  ||
-                    inet->num != hport                                  ||
                     (inet->daddr && inet->daddr != rmt_addr)            ||
                     (inet->dport != rmt_port && inet->dport)            ||
                     (inet->rcv_saddr && inet->rcv_saddr != loc_addr)    ||
@@ -1221,45 +1132,29 @@ static int __udp4_lib_mcast_deliver(struct sk_buff *skb,
                                     __be32 saddr, __be32 daddr,
                                     struct hlist_head udptable[])
 {
-        struct sock *sk, *skw, *sknext;
+        struct sock *sk;
         int dif;
-        int hport = ntohs(uh->dest);
-        unsigned int hash = ipv4_hash_port_and_addr(hport, daddr);
-        unsigned int hashwild = udp_hash_port(hport);
-
-        dif = skb->dev->ifindex;
 
         read_lock(&udp_hash_lock);
-
-        sk = sk_head(&udptable[hash & (UDP_HTABLE_SIZE - 1)]);
-        skw = sk_head(&udptable[hashwild & (UDP_HTABLE_SIZE - 1)]);
-
-        sk = udp_v4_mcast_next(sk, hash, hport, daddr, uh->source, saddr, dif);
-        if (!sk) {
-                hash = hashwild;
-                sk = udp_v4_mcast_next(skw, hash, hport, daddr, uh->source,
-                        saddr, dif);
-        }
+        sk = sk_head(&udptable[ntohs(uh->dest) & (UDP_HTABLE_SIZE - 1)]);
+        dif = skb->dev->ifindex;
+        sk = udp_v4_mcast_next(sk, uh->dest, daddr, uh->source, saddr, dif);
         if (sk) {
+                struct sock *sknext = NULL;
+
                 do {
                         struct sk_buff *skb1 = skb;
-                        sknext = udp_v4_mcast_next(sk_next(sk), hash, hport,
-                                                daddr, uh->source, saddr, dif);
-                        if (!sknext && hash != hashwild) {
-                                hash = hashwild;
-                                sknext = udp_v4_mcast_next(skw, hash, hport,
-                                        daddr, uh->source, saddr, dif);
-                        }
+
+                        sknext = udp_v4_mcast_next(sk_next(sk), uh->dest, daddr,
+                                                   uh->source, saddr, dif);
                         if (sknext)
                                 skb1 = skb_clone(skb, GFP_ATOMIC);
 
                         if (skb1) {
                                 int ret = udp_queue_rcv_skb(sk, skb1);
                                 if (ret > 0)
-                                        /*
-                                         * we should probably re-process
-                                         * instead of dropping packets here.
-                                         */
+                                        /* we should probably re-process instead
+                                         * of dropping packets here. */
                                         kfree_skb(skb1);
                         }
                         sk = sknext;
@@ -1346,7 +1241,7 @@ int __udp4_lib_rcv(struct sk_buff *skb, struct hlist_head udptable[],
                 return __udp4_lib_mcast_deliver(skb, uh, saddr, daddr, udptable);
 
         sk = __udp4_lib_lookup(saddr, uh->source, daddr, uh->dest,
-                               skb->dev->ifindex, udptable);
+                               skb->dev->ifindex, udptable        );
 
         if (sk != NULL) {
                 int ret = udp_queue_rcv_skb(sk, skb);