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