~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/netfilter/ipvs/ip_vs_dh.c

Version: ~ [ linux-5.17-rc1 ] ~ [ linux-5.16.2 ] ~ [ linux-5.15.16 ] ~ [ linux-5.14.21 ] ~ [ linux-5.13.19 ] ~ [ linux-5.12.19 ] ~ [ linux-5.11.22 ] ~ [ linux-5.10.93 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.173 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.225 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.262 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.297 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.299 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * IPVS:        Destination Hashing scheduling module
  3  *
  4  * Authors:     Wensong Zhang <wensong@gnuchina.org>
  5  *
  6  *              Inspired by the consistent hashing scheduler patch from
  7  *              Thomas Proell <proellt@gmx.de>
  8  *
  9  *              This program is free software; you can redistribute it and/or
 10  *              modify it under the terms of the GNU General Public License
 11  *              as published by the Free Software Foundation; either version
 12  *              2 of the License, or (at your option) any later version.
 13  *
 14  * Changes:
 15  *
 16  */
 17 
 18 /*
 19  * The dh algorithm is to select server by the hash key of destination IP
 20  * address. The pseudo code is as follows:
 21  *
 22  *       n <- servernode[dest_ip];
 23  *       if (n is dead) OR
 24  *          (n is overloaded) OR (n.weight <= 0) then
 25  *                 return NULL;
 26  *
 27  *       return n;
 28  *
 29  * Notes that servernode is a 256-bucket hash table that maps the hash
 30  * index derived from packet destination IP address to the current server
 31  * array. If the dh scheduler is used in cache cluster, it is good to
 32  * combine it with cache_bypass feature. When the statically assigned
 33  * server is dead or overloaded, the load balancer can bypass the cache
 34  * server and send requests to the original server directly.
 35  *
 36  */
 37 
 38 #define KMSG_COMPONENT "IPVS"
 39 #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
 40 
 41 #include <linux/ip.h>
 42 #include <linux/slab.h>
 43 #include <linux/module.h>
 44 #include <linux/kernel.h>
 45 #include <linux/skbuff.h>
 46 #include <linux/hash.h>
 47 
 48 #include <net/ip_vs.h>
 49 
 50 
 51 /*
 52  *      IPVS DH bucket
 53  */
 54 struct ip_vs_dh_bucket {
 55         struct ip_vs_dest __rcu *dest;  /* real server (cache) */
 56 };
 57 
 58 /*
 59  *     for IPVS DH entry hash table
 60  */
 61 #ifndef CONFIG_IP_VS_DH_TAB_BITS
 62 #define CONFIG_IP_VS_DH_TAB_BITS        8
 63 #endif
 64 #define IP_VS_DH_TAB_BITS               CONFIG_IP_VS_DH_TAB_BITS
 65 #define IP_VS_DH_TAB_SIZE               (1 << IP_VS_DH_TAB_BITS)
 66 #define IP_VS_DH_TAB_MASK               (IP_VS_DH_TAB_SIZE - 1)
 67 
 68 struct ip_vs_dh_state {
 69         struct ip_vs_dh_bucket          buckets[IP_VS_DH_TAB_SIZE];
 70         struct rcu_head                 rcu_head;
 71 };
 72 
 73 /*
 74  *      Returns hash value for IPVS DH entry
 75  */
 76 static inline unsigned int ip_vs_dh_hashkey(int af, const union nf_inet_addr *addr)
 77 {
 78         __be32 addr_fold = addr->ip;
 79 
 80 #ifdef CONFIG_IP_VS_IPV6
 81         if (af == AF_INET6)
 82                 addr_fold = addr->ip6[0]^addr->ip6[1]^
 83                             addr->ip6[2]^addr->ip6[3];
 84 #endif
 85         return hash_32(ntohl(addr_fold), IP_VS_DH_TAB_BITS);
 86 }
 87 
 88 
 89 /*
 90  *      Get ip_vs_dest associated with supplied parameters.
 91  */
 92 static inline struct ip_vs_dest *
 93 ip_vs_dh_get(int af, struct ip_vs_dh_state *s, const union nf_inet_addr *addr)
 94 {
 95         return rcu_dereference(s->buckets[ip_vs_dh_hashkey(af, addr)].dest);
 96 }
 97 
 98 
 99 /*
100  *      Assign all the hash buckets of the specified table with the service.
101  */
102 static int
103 ip_vs_dh_reassign(struct ip_vs_dh_state *s, struct ip_vs_service *svc)
104 {
105         int i;
106         struct ip_vs_dh_bucket *b;
107         struct list_head *p;
108         struct ip_vs_dest *dest;
109         bool empty;
110 
111         b = &s->buckets[0];
112         p = &svc->destinations;
113         empty = list_empty(p);
114         for (i=0; i<IP_VS_DH_TAB_SIZE; i++) {
115                 dest = rcu_dereference_protected(b->dest, 1);
116                 if (dest)
117                         ip_vs_dest_put(dest);
118                 if (empty)
119                         RCU_INIT_POINTER(b->dest, NULL);
120                 else {
121                         if (p == &svc->destinations)
122                                 p = p->next;
123 
124                         dest = list_entry(p, struct ip_vs_dest, n_list);
125                         ip_vs_dest_hold(dest);
126                         RCU_INIT_POINTER(b->dest, dest);
127 
128                         p = p->next;
129                 }
130                 b++;
131         }
132         return 0;
133 }
134 
135 
136 /*
137  *      Flush all the hash buckets of the specified table.
138  */
139 static void ip_vs_dh_flush(struct ip_vs_dh_state *s)
140 {
141         int i;
142         struct ip_vs_dh_bucket *b;
143         struct ip_vs_dest *dest;
144 
145         b = &s->buckets[0];
146         for (i=0; i<IP_VS_DH_TAB_SIZE; i++) {
147                 dest = rcu_dereference_protected(b->dest, 1);
148                 if (dest) {
149                         ip_vs_dest_put(dest);
150                         RCU_INIT_POINTER(b->dest, NULL);
151                 }
152                 b++;
153         }
154 }
155 
156 
157 static int ip_vs_dh_init_svc(struct ip_vs_service *svc)
158 {
159         struct ip_vs_dh_state *s;
160 
161         /* allocate the DH table for this service */
162         s = kzalloc(sizeof(struct ip_vs_dh_state), GFP_KERNEL);
163         if (s == NULL)
164                 return -ENOMEM;
165 
166         svc->sched_data = s;
167         IP_VS_DBG(6, "DH hash table (memory=%zdbytes) allocated for "
168                   "current service\n",
169                   sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE);
170 
171         /* assign the hash buckets with current dests */
172         ip_vs_dh_reassign(s, svc);
173 
174         return 0;
175 }
176 
177 
178 static void ip_vs_dh_done_svc(struct ip_vs_service *svc)
179 {
180         struct ip_vs_dh_state *s = svc->sched_data;
181 
182         /* got to clean up hash buckets here */
183         ip_vs_dh_flush(s);
184 
185         /* release the table itself */
186         kfree_rcu(s, rcu_head);
187         IP_VS_DBG(6, "DH hash table (memory=%zdbytes) released\n",
188                   sizeof(struct ip_vs_dh_bucket)*IP_VS_DH_TAB_SIZE);
189 }
190 
191 
192 static int ip_vs_dh_dest_changed(struct ip_vs_service *svc,
193                                  struct ip_vs_dest *dest)
194 {
195         struct ip_vs_dh_state *s = svc->sched_data;
196 
197         /* assign the hash buckets with the updated service */
198         ip_vs_dh_reassign(s, svc);
199 
200         return 0;
201 }
202 
203 
204 /*
205  *      If the dest flags is set with IP_VS_DEST_F_OVERLOAD,
206  *      consider that the server is overloaded here.
207  */
208 static inline int is_overloaded(struct ip_vs_dest *dest)
209 {
210         return dest->flags & IP_VS_DEST_F_OVERLOAD;
211 }
212 
213 
214 /*
215  *      Destination hashing scheduling
216  */
217 static struct ip_vs_dest *
218 ip_vs_dh_schedule(struct ip_vs_service *svc, const struct sk_buff *skb,
219                   struct ip_vs_iphdr *iph)
220 {
221         struct ip_vs_dest *dest;
222         struct ip_vs_dh_state *s;
223 
224         IP_VS_DBG(6, "%s(): Scheduling...\n", __func__);
225 
226         s = (struct ip_vs_dh_state *) svc->sched_data;
227         dest = ip_vs_dh_get(svc->af, s, &iph->daddr);
228         if (!dest
229             || !(dest->flags & IP_VS_DEST_F_AVAILABLE)
230             || atomic_read(&dest->weight) <= 0
231             || is_overloaded(dest)) {
232                 ip_vs_scheduler_err(svc, "no destination available");
233                 return NULL;
234         }
235 
236         IP_VS_DBG_BUF(6, "DH: destination IP address %s --> server %s:%d\n",
237                       IP_VS_DBG_ADDR(svc->af, &iph->daddr),
238                       IP_VS_DBG_ADDR(dest->af, &dest->addr),
239                       ntohs(dest->port));
240 
241         return dest;
242 }
243 
244 
245 /*
246  *      IPVS DH Scheduler structure
247  */
248 static struct ip_vs_scheduler ip_vs_dh_scheduler =
249 {
250         .name =                 "dh",
251         .refcnt =               ATOMIC_INIT(0),
252         .module =               THIS_MODULE,
253         .n_list =               LIST_HEAD_INIT(ip_vs_dh_scheduler.n_list),
254         .init_service =         ip_vs_dh_init_svc,
255         .done_service =         ip_vs_dh_done_svc,
256         .add_dest =             ip_vs_dh_dest_changed,
257         .del_dest =             ip_vs_dh_dest_changed,
258         .schedule =             ip_vs_dh_schedule,
259 };
260 
261 
262 static int __init ip_vs_dh_init(void)
263 {
264         return register_ip_vs_scheduler(&ip_vs_dh_scheduler);
265 }
266 
267 
268 static void __exit ip_vs_dh_cleanup(void)
269 {
270         unregister_ip_vs_scheduler(&ip_vs_dh_scheduler);
271         synchronize_rcu();
272 }
273 
274 
275 module_init(ip_vs_dh_init);
276 module_exit(ip_vs_dh_cleanup);
277 MODULE_LICENSE("GPL");
278 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp