aboutsummaryrefslogtreecommitdiffhomepage
path: root/src/core/surface/channel_create.c
blob: d069a04a9a83bb89bc3fdab349177bfd21b2ca58 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
/*
 *
 * Copyright 2015, Google Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 *     * Redistributions of source code must retain the above copyright
 * notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above
 * copyright notice, this list of conditions and the following disclaimer
 * in the documentation and/or other materials provided with the
 * distribution.
 *     * Neither the name of Google Inc. nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "src/core/iomgr/sockaddr.h"

#include <grpc/grpc.h>

#include <stdlib.h>
#include <string.h>

#include "src/core/channel/census_filter.h"
#include "src/core/channel/channel_args.h"
#include "src/core/channel/client_channel.h"
#include "src/core/channel/client_setup.h"
#include "src/core/channel/connected_channel.h"
#include "src/core/channel/http_client_filter.h"
#include "src/core/iomgr/endpoint.h"
#include "src/core/iomgr/resolve_address.h"
#include "src/core/iomgr/tcp_client.h"
#include "src/core/surface/channel.h"
#include "src/core/surface/client.h"
#include "src/core/support/string.h"
#include "src/core/transport/chttp2_transport.h"
#include <grpc/support/alloc.h>
#include <grpc/support/log.h>
#include <grpc/support/string_util.h>
#include <grpc/support/sync.h>
#include <grpc/support/useful.h>

typedef struct setup setup;

/* A single setup request (started via initiate) */
typedef struct {
  grpc_client_setup_request *cs_request;
  setup *setup;
  /* Resolved addresses, or null if resolution not yet completed */
  grpc_resolved_addresses *resolved;
  /* which address in resolved should we pick for the next connection attempt */
  size_t resolved_index;
} request;

/* Global setup logic (may be running many simultaneous setup requests, but
   with only one 'active' */
struct setup {
  const char *target;
  grpc_transport_setup_callback setup_callback;
  void *setup_user_data;
};

static int maybe_try_next_resolved(request *r);

static void done(request *r, int was_successful) {
  grpc_client_setup_request_finish(r->cs_request, was_successful);
  if (r->resolved) {
    grpc_resolved_addresses_destroy(r->resolved);
  }
  gpr_free(r);
}

/* connection callback: tcp is either valid, or null on error */
static void on_connect(void *rp, grpc_endpoint *tcp) {
  request *r = rp;

  if (!grpc_client_setup_request_should_continue(r->cs_request, "on_connect")) {
    if (tcp) {
      grpc_endpoint_shutdown(tcp);
      grpc_endpoint_destroy(tcp);
    }
    done(r, 0);
    return;
  }

  if (!tcp) {
    if (!maybe_try_next_resolved(r)) {
      done(r, 0);
      return;
    } else {
      return;
    }
  } else if (grpc_client_setup_cb_begin(r->cs_request, "on_connect")) {
    grpc_create_chttp2_transport(
        r->setup->setup_callback, r->setup->setup_user_data,
        grpc_client_setup_get_channel_args(r->cs_request), tcp, NULL, 0,
        grpc_client_setup_get_mdctx(r->cs_request), 1);
    grpc_client_setup_cb_end(r->cs_request, "on_connect");
    done(r, 1);
    return;
  } else {
    done(r, 0);
  }
}

/* attempt to connect to the next available resolved address */
static int maybe_try_next_resolved(request *r) {
  grpc_resolved_address *addr;
  if (!r->resolved) return 0;
  if (r->resolved_index == r->resolved->naddrs) return 0;
  addr = &r->resolved->addrs[r->resolved_index++];
  grpc_tcp_client_connect(
      on_connect, r, grpc_client_setup_get_interested_parties(r->cs_request),
      (struct sockaddr *)&addr->addr, addr->len,
      grpc_client_setup_request_deadline(r->cs_request));
  return 1;
}

/* callback for when our target address has been resolved */
static void on_resolved(void *rp, grpc_resolved_addresses *resolved) {
  request *r = rp;

  /* if we're not still the active request, abort */
  if (!grpc_client_setup_request_should_continue(r->cs_request,
                                                 "on_resolved")) {
    if (resolved) {
      grpc_resolved_addresses_destroy(resolved);
    }
    done(r, 0);
    return;
  }

  if (!resolved) {
    done(r, 0);
    return;
  } else {
    r->resolved = resolved;
    r->resolved_index = 0;
    if (!maybe_try_next_resolved(r)) {
      done(r, 0);
    }
  }
}

static void initiate_setup(void *sp, grpc_client_setup_request *cs_request) {
  request *r = gpr_malloc(sizeof(request));
  r->setup = sp;
  r->cs_request = cs_request;
  r->resolved = NULL;
  r->resolved_index = 0;
  /* TODO(klempner): Make grpc_resolve_address respect deadline */
  grpc_resolve_address(r->setup->target, "http", on_resolved, r);
}

static void done_setup(void *sp) {
  setup *s = sp;
  gpr_free((void *)s->target);
  gpr_free(s);
}

static grpc_transport_setup_result complete_setup(void *channel_stack,
                                                  grpc_transport *transport,
                                                  grpc_mdctx *mdctx) {
  static grpc_channel_filter const *extra_filters[] = {
      &grpc_http_client_filter};
  return grpc_client_channel_transport_setup_complete(
      channel_stack, transport, extra_filters, GPR_ARRAY_SIZE(extra_filters),
      mdctx);
}

/* Create a client channel:
   Asynchronously: - resolve target
                   - connect to it (trying alternatives as presented)
                   - perform handshakes */
grpc_channel *grpc_channel_create(const char *target,
                                  const grpc_channel_args *args) {
  setup *s = gpr_malloc(sizeof(setup));
  grpc_mdctx *mdctx = grpc_mdctx_create();
  grpc_channel *channel = NULL;
#define MAX_FILTERS 3
  const grpc_channel_filter *filters[MAX_FILTERS];
  int n = 0;
  filters[n++] = &grpc_client_surface_filter;
  /* TODO(census)
  if (grpc_channel_args_is_census_enabled(args)) {
    filters[n++] = &grpc_client_census_filter;
    } */
  filters[n++] = &grpc_client_channel_filter;
  GPR_ASSERT(n <= MAX_FILTERS);
  channel = grpc_channel_create_from_filters(filters, n, args, mdctx, 1);

  s->target = gpr_strdup(target);
  s->setup_callback = complete_setup;
  s->setup_user_data = grpc_channel_get_channel_stack(channel);

  grpc_client_setup_create_and_attach(grpc_channel_get_channel_stack(channel),
                                      args, mdctx, initiate_setup, done_setup,
                                      s);

  return channel;
}