1
2 /*
3 * Copyright (C) Igor Sysoev
4 * Copyright (C) Nginx, Inc.
5 */
6
7
8 #include <ngx_config.h>
9 #include <ngx_core.h>
10 #include <ngx_http.h>
11
12
13 typedef struct {
14 /* the round robin data must be first */
15 ngx_http_upstream_rr_peer_data_t rrp;
16
17 ngx_uint_t hash;
18
19 u_char addrlen;
20 u_char *addr;
21
22 u_char tries;
23
24 ngx_event_get_peer_pt get_rr_peer;
25 } ngx_http_upstream_ip_hash_peer_data_t;
26
27
28 static ngx_int_t ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r,
29 ngx_http_upstream_srv_conf_t *us);
30 static ngx_int_t ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc,
31 void *data);
32 static char *ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd,
33 void *conf);
34
35
36 static ngx_command_t ngx_http_upstream_ip_hash_commands[] = {
37
38 { ngx_string("ip_hash"),
39 NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS,
40 ngx_http_upstream_ip_hash,
41 0,
42 0,
43 NULL },
44
45 ngx_null_command
46 };
47
48
49 static ngx_http_module_t ngx_http_upstream_ip_hash_module_ctx = {
50 NULL, /* preconfiguration */
51 NULL, /* postconfiguration */
52
53 NULL, /* create main configuration */
54 NULL, /* init main configuration */
55
56 NULL, /* create server configuration */
57 NULL, /* merge server configuration */
58
59 NULL, /* create location configuration */
60 NULL /* merge location configuration */
61 };
62
63
64 ngx_module_t ngx_http_upstream_ip_hash_module = {
65 NGX_MODULE_V1,
66 &ngx_http_upstream_ip_hash_module_ctx, /* module context */
67 ngx_http_upstream_ip_hash_commands, /* module directives */
68 NGX_HTTP_MODULE, /* module type */
69 NULL, /* init master */
70 NULL, /* init module */
71 NULL, /* init process */
72 NULL, /* init thread */
73 NULL, /* exit thread */
74 NULL, /* exit process */
75 NULL, /* exit master */
76 NGX_MODULE_V1_PADDING
77 };
78
79
80 static u_char ngx_http_upstream_ip_hash_pseudo_addr[3];
81
82
83 static ngx_int_t
ngx_http_upstream_init_ip_hash(ngx_conf_t * cf,ngx_http_upstream_srv_conf_t * us)84 ngx_http_upstream_init_ip_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
85 {
86 if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
87 return NGX_ERROR;
88 }
89
90 us->peer.init = ngx_http_upstream_init_ip_hash_peer;
91
92 return NGX_OK;
93 }
94
95
96 static ngx_int_t
ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t * r,ngx_http_upstream_srv_conf_t * us)97 ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r,
98 ngx_http_upstream_srv_conf_t *us)
99 {
100 struct sockaddr_in *sin;
101 #if (NGX_HAVE_INET6)
102 struct sockaddr_in6 *sin6;
103 #endif
104 ngx_http_upstream_ip_hash_peer_data_t *iphp;
105
106 iphp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_ip_hash_peer_data_t));
107 if (iphp == NULL) {
108 return NGX_ERROR;
109 }
110
111 r->upstream->peer.data = &iphp->rrp;
112
113 if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
114 return NGX_ERROR;
115 }
116
117 r->upstream->peer.get = ngx_http_upstream_get_ip_hash_peer;
118
119 switch (r->connection->sockaddr->sa_family) {
120
121 case AF_INET:
122 sin = (struct sockaddr_in *) r->connection->sockaddr;
123 iphp->addr = (u_char *) &sin->sin_addr.s_addr;
124 iphp->addrlen = 3;
125 break;
126
127 #if (NGX_HAVE_INET6)
128 case AF_INET6:
129 sin6 = (struct sockaddr_in6 *) r->connection->sockaddr;
130 iphp->addr = (u_char *) &sin6->sin6_addr.s6_addr;
131 iphp->addrlen = 16;
132 break;
133 #endif
134
135 default:
136 iphp->addr = ngx_http_upstream_ip_hash_pseudo_addr;
137 iphp->addrlen = 3;
138 }
139
140 iphp->hash = 89;
141 iphp->tries = 0;
142 iphp->get_rr_peer = ngx_http_upstream_get_round_robin_peer;
143
144 return NGX_OK;
145 }
146
147
148 static ngx_int_t
ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t * pc,void * data)149 ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
150 {
151 ngx_http_upstream_ip_hash_peer_data_t *iphp = data;
152
153 time_t now;
154 ngx_int_t w;
155 uintptr_t m;
156 ngx_uint_t i, n, p, hash;
157 ngx_http_upstream_rr_peer_t *peer;
158
159 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
160 "get ip hash peer, try: %ui", pc->tries);
161
162 /* TODO: cached */
163
164 ngx_http_upstream_rr_peers_rlock(iphp->rrp.peers);
165
166 if (iphp->tries > 20 || iphp->rrp.peers->single) {
167 ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
168 return iphp->get_rr_peer(pc, &iphp->rrp);
169 }
170
171 now = ngx_time();
172
173 pc->cached = 0;
174 pc->connection = NULL;
175
176 hash = iphp->hash;
177
178 for ( ;; ) {
179
180 for (i = 0; i < (ngx_uint_t) iphp->addrlen; i++) {
181 hash = (hash * 113 + iphp->addr[i]) % 6271;
182 }
183
184 w = hash % iphp->rrp.peers->total_weight;
185 peer = iphp->rrp.peers->peer;
186 p = 0;
187
188 while (w >= peer->weight) {
189 w -= peer->weight;
190 peer = peer->next;
191 p++;
192 }
193
194 n = p / (8 * sizeof(uintptr_t));
195 m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
196
197 if (iphp->rrp.tried[n] & m) {
198 goto next;
199 }
200
201 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
202 "get ip hash peer, hash: %ui %04XL", p, (uint64_t) m);
203
204 ngx_http_upstream_rr_peer_lock(iphp->rrp.peers, peer);
205
206 if (peer->down) {
207 ngx_http_upstream_rr_peer_unlock(iphp->rrp.peers, peer);
208 goto next;
209 }
210
211 if (peer->max_fails
212 && peer->fails >= peer->max_fails
213 && now - peer->checked <= peer->fail_timeout)
214 {
215 ngx_http_upstream_rr_peer_unlock(iphp->rrp.peers, peer);
216 goto next;
217 }
218
219 if (peer->max_conns && peer->conns >= peer->max_conns) {
220 ngx_http_upstream_rr_peer_unlock(iphp->rrp.peers, peer);
221 goto next;
222 }
223
224 break;
225
226 next:
227
228 if (++iphp->tries > 20) {
229 ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
230 return iphp->get_rr_peer(pc, &iphp->rrp);
231 }
232 }
233
234 iphp->rrp.current = peer;
235
236 pc->sockaddr = peer->sockaddr;
237 pc->socklen = peer->socklen;
238 pc->name = &peer->name;
239
240 peer->conns++;
241
242 if (now - peer->checked > peer->fail_timeout) {
243 peer->checked = now;
244 }
245
246 ngx_http_upstream_rr_peer_unlock(iphp->rrp.peers, peer);
247 ngx_http_upstream_rr_peers_unlock(iphp->rrp.peers);
248
249 iphp->rrp.tried[n] |= m;
250 iphp->hash = hash;
251
252 return NGX_OK;
253 }
254
255
256 static char *
ngx_http_upstream_ip_hash(ngx_conf_t * cf,ngx_command_t * cmd,void * conf)257 ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
258 {
259 ngx_http_upstream_srv_conf_t *uscf;
260
261 uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);
262
263 if (uscf->peer.init_upstream) {
264 ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
265 "load balancing method redefined");
266 }
267
268 uscf->peer.init_upstream = ngx_http_upstream_init_ip_hash;
269
270 uscf->flags = NGX_HTTP_UPSTREAM_CREATE
271 |NGX_HTTP_UPSTREAM_WEIGHT
272 |NGX_HTTP_UPSTREAM_MAX_CONNS
273 |NGX_HTTP_UPSTREAM_MAX_FAILS
274 |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
275 |NGX_HTTP_UPSTREAM_DOWN;
276
277 return NGX_CONF_OK;
278 }
279