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 u_char addr[3];
19
20 u_char tries;
21
22 ngx_event_get_peer_pt get_rr_peer;
23 } ngx_http_upstream_ip_hash_peer_data_t;
24
25
26 static ngx_int_t ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r,
27 ngx_http_upstream_srv_conf_t *us);
28 static ngx_int_t ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc,
29 void *data);
30 static char *ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd,
31 void *conf);
32
33
34 static ngx_command_t ngx_http_upstream_ip_hash_commands[] = {
35
36 { ngx_string("ip_hash"),
37 NGX_HTTP_UPS_CONF|NGX_CONF_NOARGS,
38 ngx_http_upstream_ip_hash,
39 0,
40 0,
41 NULL },
42
43 ngx_null_command
44 };
45
46
47 static ngx_http_module_t ngx_http_upstream_ip_hash_module_ctx = {
48 NULL, /* preconfiguration */
49 NULL, /* postconfiguration */
50
51 NULL, /* create main configuration */
52 NULL, /* init main configuration */
53
54 NULL, /* create server configuration */
55 NULL, /* merge server configuration */
56
57 NULL, /* create location configuration */
58 NULL /* merge location configuration */
59 };
60
61
62 ngx_module_t ngx_http_upstream_ip_hash_module = {
63 NGX_MODULE_V1,
64 &ngx_http_upstream_ip_hash_module_ctx, /* module context */
65 ngx_http_upstream_ip_hash_commands, /* module directives */
66 NGX_HTTP_MODULE, /* module type */
67 NULL, /* init master */
68 NULL, /* init module */
69 NULL, /* init process */
70 NULL, /* init thread */
71 NULL, /* exit thread */
72 NULL, /* exit process */
73 NULL, /* exit master */
74 NGX_MODULE_V1_PADDING
75 };
76
77
78 ngx_int_t
79 ngx_http_upstream_init_ip_hash(ngx_conf_t *cf, ngx_http_upstream_srv_conf_t *us)
80 {
81 if (ngx_http_upstream_init_round_robin(cf, us) != NGX_OK) {
82 return NGX_ERROR;
83 }
84
85 us->peer.init = ngx_http_upstream_init_ip_hash_peer;
86
87 return NGX_OK;
88 }
89
90
91 static ngx_int_t
92 ngx_http_upstream_init_ip_hash_peer(ngx_http_request_t *r,
93 ngx_http_upstream_srv_conf_t *us)
94 {
95 u_char *p;
96 struct sockaddr_in *sin;
97 ngx_http_upstream_ip_hash_peer_data_t *iphp;
98
99 iphp = ngx_palloc(r->pool, sizeof(ngx_http_upstream_ip_hash_peer_data_t));
100 if (iphp == NULL) {
101 return NGX_ERROR;
102 }
103
104 r->upstream->peer.data = &iphp->rrp;
105
106 if (ngx_http_upstream_init_round_robin_peer(r, us) != NGX_OK) {
107 return NGX_ERROR;
108 }
109
110 r->upstream->peer.get = ngx_http_upstream_get_ip_hash_peer;
111
112 /* AF_INET only */
113
114 if (r->connection->sockaddr->sa_family == AF_INET) {
115
116 sin = (struct sockaddr_in *) r->connection->sockaddr;
117 p = (u_char *) &sin->sin_addr.s_addr;
118 iphp->addr[0] = p[0];
119 iphp->addr[1] = p[1];
120 iphp->addr[2] = p[2];
121
122 } else {
123 iphp->addr[0] = 0;
124 iphp->addr[1] = 0;
125 iphp->addr[2] = 0;
126 }
127
128 iphp->hash = 89;
129 iphp->tries = 0;
130 iphp->get_rr_peer = ngx_http_upstream_get_round_robin_peer;
131
132 return NGX_OK;
133 }
134
135
136 static ngx_int_t
137 ngx_http_upstream_get_ip_hash_peer(ngx_peer_connection_t *pc, void *data)
138 {
139 ngx_http_upstream_ip_hash_peer_data_t *iphp = data;
140
141 time_t now;
142 uintptr_t m;
143 ngx_uint_t i, n, p, hash;
144 ngx_http_upstream_rr_peer_t *peer;
145
146 ngx_log_debug1(NGX_LOG_DEBUG_HTTP, pc->log, 0,
147 "get ip hash peer, try: %ui", pc->tries);
148
149 /* TODO: cached */
150
151 if (iphp->tries > 20 || iphp->rrp.peers->single) {
152 return iphp->get_rr_peer(pc, &iphp->rrp);
153 }
154
155 now = ngx_time();
156
157 pc->cached = 0;
158 pc->connection = NULL;
159
160 hash = iphp->hash;
161
162 for ( ;; ) {
163
164 for (i = 0; i < 3; i++) {
165 hash = (hash * 113 + iphp->addr[i]) % 6271;
166 }
167
168 p = hash % iphp->rrp.peers->number;
169
170 n = p / (8 * sizeof(uintptr_t));
171 m = (uintptr_t) 1 << p % (8 * sizeof(uintptr_t));
172
173 if (!(iphp->rrp.tried[n] & m)) {
174
175 ngx_log_debug2(NGX_LOG_DEBUG_HTTP, pc->log, 0,
176 "get ip hash peer, hash: %ui %04XA", p, m);
177
178 peer = &iphp->rrp.peers->peer[p];
179
180 /* ngx_lock_mutex(iphp->rrp.peers->mutex); */
181
182 if (!peer->down) {
183
184 if (peer->max_fails == 0 || peer->fails < peer->max_fails) {
185 break;
186 }
187
188 if (now - peer->accessed > peer->fail_timeout) {
189 peer->fails = 0;
190 break;
191 }
192 }
193
194 iphp->rrp.tried[n] |= m;
195
196 /* ngx_unlock_mutex(iphp->rrp.peers->mutex); */
197
198 pc->tries--;
199 }
200
201 if (++iphp->tries >= 20) {
202 return iphp->get_rr_peer(pc, &iphp->rrp);
203 }
204 }
205
206 iphp->rrp.current = p;
207
208 pc->sockaddr = peer->sockaddr;
209 pc->socklen = peer->socklen;
210 pc->name = &peer->name;
211
212 /* ngx_unlock_mutex(iphp->rrp.peers->mutex); */
213
214 iphp->rrp.tried[n] |= m;
215 iphp->hash = hash;
216
217 return NGX_OK;
218 }
219
220
221 static char *
222 ngx_http_upstream_ip_hash(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
223 {
224 ngx_http_upstream_srv_conf_t *uscf;
225
226 uscf = ngx_http_conf_get_module_srv_conf(cf, ngx_http_upstream_module);
227
228 uscf->peer.init_upstream = ngx_http_upstream_init_ip_hash;
229
230 uscf->flags = NGX_HTTP_UPSTREAM_CREATE
231 |NGX_HTTP_UPSTREAM_MAX_FAILS
232 |NGX_HTTP_UPSTREAM_FAIL_TIMEOUT
233 |NGX_HTTP_UPSTREAM_DOWN;
234
235 return NGX_CONF_OK;
236 }
237
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