nginx/src/http/modules/ngx_http_upstream_ip_hash_module.c

   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 }