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-rw-r--r--net/ipv4/udp.c55
1 files changed, 39 insertions, 16 deletions
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index cf5ab0581eba..b7faffe5c029 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -120,8 +120,11 @@ EXPORT_SYMBOL(sysctl_udp_wmem_min);
120atomic_t udp_memory_allocated; 120atomic_t udp_memory_allocated;
121EXPORT_SYMBOL(udp_memory_allocated); 121EXPORT_SYMBOL(udp_memory_allocated);
122 122
123#define PORTS_PER_CHAIN (65536 / UDP_HTABLE_SIZE)
124
123static int udp_lib_lport_inuse(struct net *net, __u16 num, 125static int udp_lib_lport_inuse(struct net *net, __u16 num,
124 const struct udp_hslot *hslot, 126 const struct udp_hslot *hslot,
127 unsigned long *bitmap,
125 struct sock *sk, 128 struct sock *sk,
126 int (*saddr_comp)(const struct sock *sk1, 129 int (*saddr_comp)(const struct sock *sk1,
127 const struct sock *sk2)) 130 const struct sock *sk2))
@@ -132,12 +135,17 @@ static int udp_lib_lport_inuse(struct net *net, __u16 num,
132 sk_nulls_for_each(sk2, node, &hslot->head) 135 sk_nulls_for_each(sk2, node, &hslot->head)
133 if (net_eq(sock_net(sk2), net) && 136 if (net_eq(sock_net(sk2), net) &&
134 sk2 != sk && 137 sk2 != sk &&
135 sk2->sk_hash == num && 138 (bitmap || sk2->sk_hash == num) &&
136 (!sk2->sk_reuse || !sk->sk_reuse) && 139 (!sk2->sk_reuse || !sk->sk_reuse) &&
137 (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if 140 (!sk2->sk_bound_dev_if || !sk->sk_bound_dev_if
138 || sk2->sk_bound_dev_if == sk->sk_bound_dev_if) && 141 || sk2->sk_bound_dev_if == sk->sk_bound_dev_if) &&
139 (*saddr_comp)(sk, sk2)) 142 (*saddr_comp)(sk, sk2)) {
140 return 1; 143 if (bitmap)
144 __set_bit(sk2->sk_hash / UDP_HTABLE_SIZE,
145 bitmap);
146 else
147 return 1;
148 }
141 return 0; 149 return 0;
142} 150}
143 151
@@ -160,32 +168,47 @@ int udp_lib_get_port(struct sock *sk, unsigned short snum,
160 if (!snum) { 168 if (!snum) {
161 int low, high, remaining; 169 int low, high, remaining;
162 unsigned rand; 170 unsigned rand;
163 unsigned short first; 171 unsigned short first, last;
172 DECLARE_BITMAP(bitmap, PORTS_PER_CHAIN);
164 173
165 inet_get_local_port_range(&low, &high); 174 inet_get_local_port_range(&low, &high);
166 remaining = (high - low) + 1; 175 remaining = (high - low) + 1;
167 176
168 rand = net_random(); 177 rand = net_random();
169 snum = first = rand % remaining + low; 178 first = (((u64)rand * remaining) >> 32) + low;
170 rand |= 1; 179 /*
171 for (;;) { 180 * force rand to be an odd multiple of UDP_HTABLE_SIZE
172 hslot = &udptable->hash[udp_hashfn(net, snum)]; 181 */
182 rand = (rand | 1) * UDP_HTABLE_SIZE;
183 for (last = first + UDP_HTABLE_SIZE; first != last; first++) {
184 hslot = &udptable->hash[udp_hashfn(net, first)];
185 bitmap_zero(bitmap, PORTS_PER_CHAIN);
173 spin_lock_bh(&hslot->lock); 186 spin_lock_bh(&hslot->lock);
174 if (!udp_lib_lport_inuse(net, snum, hslot, sk, saddr_comp)) 187 udp_lib_lport_inuse(net, snum, hslot, bitmap, sk,
175 break; 188 saddr_comp);
176 spin_unlock_bh(&hslot->lock); 189
190 snum = first;
191 /*
192 * Iterate on all possible values of snum for this hash.
193 * Using steps of an odd multiple of UDP_HTABLE_SIZE
194 * give us randomization and full range coverage.
195 */
177 do { 196 do {
178 snum = snum + rand; 197 if (low <= snum && snum <= high &&
179 } while (snum < low || snum > high); 198 !test_bit(snum / UDP_HTABLE_SIZE, bitmap))
180 if (snum == first) 199 goto found;
181 goto fail; 200 snum += rand;
201 } while (snum != first);
202 spin_unlock_bh(&hslot->lock);
182 } 203 }
204 goto fail;
183 } else { 205 } else {
184 hslot = &udptable->hash[udp_hashfn(net, snum)]; 206 hslot = &udptable->hash[udp_hashfn(net, snum)];
185 spin_lock_bh(&hslot->lock); 207 spin_lock_bh(&hslot->lock);
186 if (udp_lib_lport_inuse(net, snum, hslot, sk, saddr_comp)) 208 if (udp_lib_lport_inuse(net, snum, hslot, NULL, sk, saddr_comp))
187 goto fail_unlock; 209 goto fail_unlock;
188 } 210 }
211found:
189 inet_sk(sk)->num = snum; 212 inet_sk(sk)->num = snum;
190 sk->sk_hash = snum; 213 sk->sk_hash = snum;
191 if (sk_unhashed(sk)) { 214 if (sk_unhashed(sk)) {