//
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// Copyright 2020 Staysail Systems, Inc. <info@staysail.tech>
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// Copyright 2018 Capitar IT Group BV <info@capitar.com>
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//
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// This software is supplied under the terms of the MIT License, a
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// copy of which should be located in the distribution where this
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// file was obtained (LICENSE.txt). A copy of the license may also be
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// found online at https://opensource.org/licenses/MIT.
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//
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#include <string.h>
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#include "core/nng_impl.h"
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#include "nng/protocol/reqrep0/rep.h"
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// Response protocol. The REP protocol is the "reply" side of a
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// request-reply pair. This is useful for building RPC servers, for
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// example.
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typedef struct rep0_pipe rep0_pipe;
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typedef struct rep0_sock rep0_sock;
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typedef struct rep0_ctx rep0_ctx;
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static void rep0_pipe_send_cb(void *);
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static void rep0_pipe_recv_cb(void *);
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static void rep0_pipe_fini(void *);
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struct rep0_ctx {
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rep0_sock * sock;
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uint32_t pipe_id;
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rep0_pipe * spipe; // send pipe
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nni_aio * saio; // send aio
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nni_aio * raio; // recv aio
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nni_list_node sqnode;
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nni_list_node rqnode;
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size_t btrace_len;
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uint32_t btrace[NNI_MAX_MAX_TTL + 1];
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};
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// rep0_sock is our per-socket protocol private structure.
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struct rep0_sock {
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nni_mtx lk;
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nni_atomic_int ttl;
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nni_id_map pipes;
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nni_list recvpipes; // list of pipes with data to receive
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nni_list recvq;
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rep0_ctx ctx;
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nni_pollable readable;
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nni_pollable writable;
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};
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// rep0_pipe is our per-pipe protocol private structure.
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struct rep0_pipe {
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nni_pipe * pipe;
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rep0_sock * rep;
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uint32_t id;
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nni_aio aio_send;
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nni_aio aio_recv;
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nni_list_node rnode; // receivable list linkage
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nni_list sendq; // contexts waiting to send
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bool busy;
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bool closed;
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};
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static void
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rep0_ctx_close(void *arg)
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{
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rep0_ctx * ctx = arg;
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rep0_sock *s = ctx->sock;
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nni_aio * aio;
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nni_mtx_lock(&s->lk);
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if ((aio = ctx->saio) != NULL) {
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rep0_pipe *pipe = ctx->spipe;
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ctx->saio = NULL;
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ctx->spipe = NULL;
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nni_list_remove(&pipe->sendq, ctx);
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nni_aio_finish_error(aio, NNG_ECLOSED);
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}
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if ((aio = ctx->raio) != NULL) {
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nni_list_remove(&s->recvq, ctx);
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ctx->raio = NULL;
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nni_aio_finish_error(aio, NNG_ECLOSED);
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}
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nni_mtx_unlock(&s->lk);
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}
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static void
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rep0_ctx_fini(void *arg)
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{
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rep0_ctx *ctx = arg;
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rep0_ctx_close(ctx);
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}
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static int
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rep0_ctx_init(void *carg, void *sarg)
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{
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rep0_sock *s = sarg;
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rep0_ctx * ctx = carg;
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NNI_LIST_NODE_INIT(&ctx->sqnode);
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NNI_LIST_NODE_INIT(&ctx->rqnode);
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ctx->btrace_len = 0;
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ctx->sock = s;
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ctx->pipe_id = 0;
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return (0);
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}
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static void
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rep0_ctx_cancel_send(nni_aio *aio, void *arg, int rv)
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{
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rep0_ctx * ctx = arg;
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rep0_sock *s = ctx->sock;
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nni_mtx_lock(&s->lk);
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if (ctx->saio != aio) {
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nni_mtx_unlock(&s->lk);
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return;
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}
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nni_list_node_remove(&ctx->sqnode);
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ctx->saio = NULL;
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nni_mtx_unlock(&s->lk);
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nni_msg_header_clear(nni_aio_get_msg(aio)); // reset the headers
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nni_aio_finish_error(aio, rv);
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}
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static void
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rep0_ctx_send(void *arg, nni_aio *aio)
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{
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rep0_ctx * ctx = arg;
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rep0_sock *s = ctx->sock;
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rep0_pipe *p;
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nni_msg * msg;
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int rv;
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size_t len;
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uint32_t p_id; // pipe id
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msg = nni_aio_get_msg(aio);
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nni_msg_header_clear(msg);
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if (nni_aio_begin(aio) != 0) {
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return;
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}
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nni_mtx_lock(&s->lk);
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len = ctx->btrace_len;
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p_id = ctx->pipe_id;
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// Assert "completion" of the previous req request. This ensures
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// exactly one send for one receive ordering.
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ctx->btrace_len = 0;
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ctx->pipe_id = 0;
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if (ctx == &s->ctx) {
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// No matter how this goes, we will no longer be able
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// to send on the socket (root context). That's because
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// we will have finished (successfully or otherwise) the
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// reply for the single request we got.
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nni_pollable_clear(&s->writable);
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}
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if (len == 0) {
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nni_mtx_unlock(&s->lk);
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nni_aio_finish_error(aio, NNG_ESTATE);
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return;
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}
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if ((rv = nni_msg_header_append(msg, ctx->btrace, len)) != 0) {
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nni_mtx_unlock(&s->lk);
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nni_aio_finish_error(aio, rv);
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return;
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}
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if ((p = nni_id_get(&s->pipes, p_id)) == NULL) {
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// Pipe is gone. Make this look like a good send to avoid
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// disrupting the state machine. We don't care if the peer
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// lost interest in our reply.
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nni_mtx_unlock(&s->lk);
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nni_aio_set_msg(aio, NULL);
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nni_aio_finish(aio, 0, nni_msg_len(msg));
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nni_msg_free(msg);
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return;
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}
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if (!p->busy) {
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p->busy = true;
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len = nni_msg_len(msg);
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nni_aio_set_msg(&p->aio_send, msg);
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nni_pipe_send(p->pipe, &p->aio_send);
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nni_mtx_unlock(&s->lk);
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nni_aio_set_msg(aio, NULL);
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nni_aio_finish(aio, 0, len);
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return;
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}
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if ((rv = nni_aio_schedule(aio, rep0_ctx_cancel_send, ctx)) != 0) {
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nni_mtx_unlock(&s->lk);
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nni_aio_finish_error(aio, rv);
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return;
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}
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ctx->saio = aio;
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ctx->spipe = p;
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nni_list_append(&p->sendq, ctx);
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nni_mtx_unlock(&s->lk);
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}
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static void
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rep0_sock_fini(void *arg)
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{
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rep0_sock *s = arg;
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nni_id_map_fini(&s->pipes);
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rep0_ctx_fini(&s->ctx);
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nni_pollable_fini(&s->writable);
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nni_pollable_fini(&s->readable);
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nni_mtx_fini(&s->lk);
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}
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static int
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rep0_sock_init(void *arg, nni_sock *sock)
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{
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rep0_sock *s = arg;
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NNI_ARG_UNUSED(sock);
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nni_mtx_init(&s->lk);
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nni_id_map_init(&s->pipes, 0, 0, false);
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NNI_LIST_INIT(&s->recvq, rep0_ctx, rqnode);
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NNI_LIST_INIT(&s->recvpipes, rep0_pipe, rnode);
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nni_atomic_init(&s->ttl);
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nni_atomic_set(&s->ttl, 8);
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(void) rep0_ctx_init(&s->ctx, s);
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// We start off without being either readable or writable.
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// Readability comes when there is something on the socket.
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nni_pollable_init(&s->writable);
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nni_pollable_init(&s->readable);
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return (0);
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}
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static void
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rep0_sock_open(void *arg)
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{
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NNI_ARG_UNUSED(arg);
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}
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static void
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rep0_sock_close(void *arg)
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{
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rep0_sock *s = arg;
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rep0_ctx_close(&s->ctx);
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}
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static void
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rep0_pipe_stop(void *arg)
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{
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rep0_pipe *p = arg;
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nni_aio_stop(&p->aio_send);
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nni_aio_stop(&p->aio_recv);
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}
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static void
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rep0_pipe_fini(void *arg)
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{
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rep0_pipe *p = arg;
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nng_msg * msg;
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if ((msg = nni_aio_get_msg(&p->aio_recv)) != NULL) {
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nni_aio_set_msg(&p->aio_recv, NULL);
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nni_msg_free(msg);
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}
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nni_aio_fini(&p->aio_send);
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nni_aio_fini(&p->aio_recv);
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}
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static int
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rep0_pipe_init(void *arg, nni_pipe *pipe, void *s)
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{
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rep0_pipe *p = arg;
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nni_aio_init(&p->aio_send, rep0_pipe_send_cb, p);
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nni_aio_init(&p->aio_recv, rep0_pipe_recv_cb, p);
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NNI_LIST_INIT(&p->sendq, rep0_ctx, sqnode);
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p->id = nni_pipe_id(pipe);
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p->pipe = pipe;
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p->rep = s;
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return (0);
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}
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static int
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rep0_pipe_start(void *arg)
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{
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rep0_pipe *p = arg;
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rep0_sock *s = p->rep;
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int rv;
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if (nni_pipe_peer(p->pipe) != NNG_REP0_PEER) {
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// Peer protocol mismatch.
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return (NNG_EPROTO);
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}
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nni_mtx_lock(&s->lk);
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rv = nni_id_set(&s->pipes, nni_pipe_id(p->pipe), p);
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nni_mtx_unlock(&s->lk);
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if (rv != 0) {
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return (rv);
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}
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// By definition, we have not received a request yet on this pipe,
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// so it cannot cause us to become writable.
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nni_pipe_recv(p->pipe, &p->aio_recv);
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return (0);
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}
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static void
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rep0_pipe_close(void *arg)
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{
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rep0_pipe *p = arg;
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rep0_sock *s = p->rep;
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rep0_ctx * ctx;
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nni_aio_close(&p->aio_send);
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nni_aio_close(&p->aio_recv);
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nni_mtx_lock(&s->lk);
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p->closed = true;
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if (nni_list_active(&s->recvpipes, p)) {
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// We are no longer "receivable".
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nni_list_remove(&s->recvpipes, p);
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}
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while ((ctx = nni_list_first(&p->sendq)) != NULL) {
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nni_aio *aio;
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nni_msg *msg;
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// Pipe was closed. To avoid pushing an error back to the
|
// entire socket, we pretend we completed this successfully.
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nni_list_remove(&p->sendq, ctx);
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aio = ctx->saio;
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ctx->saio = NULL;
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msg = nni_aio_get_msg(aio);
|
nni_aio_set_msg(aio, NULL);
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nni_aio_finish(aio, 0, nni_msg_len(msg));
|
nni_msg_free(msg);
|
}
|
if (p->id == s->ctx.pipe_id) {
|
// We "can" send. (Well, not really, but we will happily
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// accept a message and discard it.)
|
nni_pollable_raise(&s->writable);
|
}
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nni_id_remove(&s->pipes, nni_pipe_id(p->pipe));
|
nni_mtx_unlock(&s->lk);
|
}
|
|
static void
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rep0_pipe_send_cb(void *arg)
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{
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rep0_pipe *p = arg;
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rep0_sock *s = p->rep;
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rep0_ctx * ctx;
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nni_aio * aio;
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nni_msg * msg;
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size_t len;
|
|
if (nni_aio_result(&p->aio_send) != 0) {
|
nni_msg_free(nni_aio_get_msg(&p->aio_send));
|
nni_aio_set_msg(&p->aio_send, NULL);
|
nni_pipe_close(p->pipe);
|
return;
|
}
|
nni_mtx_lock(&s->lk);
|
p->busy = false;
|
if ((ctx = nni_list_first(&p->sendq)) == NULL) {
|
// Nothing else to send.
|
if (p->id == s->ctx.pipe_id) {
|
// Mark us ready for the other side to send!
|
nni_pollable_raise(&s->writable);
|
}
|
nni_mtx_unlock(&s->lk);
|
return;
|
}
|
|
nni_list_remove(&p->sendq, ctx);
|
aio = ctx->saio;
|
ctx->saio = NULL;
|
ctx->spipe = NULL;
|
p->busy = true;
|
msg = nni_aio_get_msg(aio);
|
len = nni_msg_len(msg);
|
nni_aio_set_msg(aio, NULL);
|
nni_aio_set_msg(&p->aio_send, msg);
|
nni_pipe_send(p->pipe, &p->aio_send);
|
|
nni_mtx_unlock(&s->lk);
|
|
nni_aio_finish_sync(aio, 0, len);
|
}
|
|
static void
|
rep0_cancel_recv(nni_aio *aio, void *arg, int rv)
|
{
|
rep0_ctx * ctx = arg;
|
rep0_sock *s = ctx->sock;
|
|
nni_mtx_lock(&s->lk);
|
if (ctx->raio == aio) {
|
nni_list_remove(&s->recvq, ctx);
|
ctx->raio = NULL;
|
nni_aio_finish_error(aio, rv);
|
}
|
nni_mtx_unlock(&s->lk);
|
}
|
|
static void
|
rep0_ctx_recv(void *arg, nni_aio *aio)
|
{
|
rep0_ctx * ctx = arg;
|
rep0_sock *s = ctx->sock;
|
rep0_pipe *p;
|
size_t len;
|
nni_msg * msg;
|
|
if (nni_aio_begin(aio) != 0) {
|
return;
|
}
|
nni_mtx_lock(&s->lk);
|
if ((p = nni_list_first(&s->recvpipes)) == NULL) {
|
int rv;
|
if ((rv = nni_aio_schedule(aio, rep0_cancel_recv, ctx)) != 0) {
|
nni_mtx_unlock(&s->lk);
|
nni_aio_finish_error(aio, rv);
|
return;
|
}
|
if (ctx->raio != NULL) {
|
// Cannot have a second receive operation pending.
|
// This could be ESTATE, or we could cancel the first
|
// with ECANCELED. We elect the former.
|
nni_mtx_unlock(&s->lk);
|
nni_aio_finish_error(aio, NNG_ESTATE);
|
return;
|
}
|
ctx->raio = aio;
|
nni_list_append(&s->recvq, ctx);
|
nni_mtx_unlock(&s->lk);
|
return;
|
}
|
msg = nni_aio_get_msg(&p->aio_recv);
|
nni_aio_set_msg(&p->aio_recv, NULL);
|
nni_list_remove(&s->recvpipes, p);
|
if (nni_list_empty(&s->recvpipes)) {
|
nni_pollable_clear(&s->readable);
|
}
|
nni_pipe_recv(p->pipe, &p->aio_recv);
|
if ((ctx == &s->ctx) && !p->busy) {
|
nni_pollable_raise(&s->writable);
|
}
|
|
len = nni_msg_header_len(msg);
|
memcpy(ctx->btrace, nni_msg_header(msg), len);
|
ctx->btrace_len = len;
|
ctx->pipe_id = nni_pipe_id(p->pipe);
|
nni_mtx_unlock(&s->lk);
|
|
nni_msg_header_clear(msg);
|
nni_aio_set_msg(aio, msg);
|
nni_aio_finish(aio, 0, nni_msg_len(msg));
|
}
|
|
static void
|
rep0_pipe_recv_cb(void *arg)
|
{
|
rep0_pipe *p = arg;
|
rep0_sock *s = p->rep;
|
rep0_ctx * ctx;
|
nni_msg * msg;
|
uint8_t * body;
|
nni_aio * aio;
|
size_t len;
|
int hops;
|
int ttl;
|
|
if (nni_aio_result(&p->aio_recv) != 0) {
|
nni_pipe_close(p->pipe);
|
return;
|
}
|
|
msg = nni_aio_get_msg(&p->aio_recv);
|
ttl = nni_atomic_get(&s->ttl);
|
|
nni_msg_set_pipe(msg, p->id);
|
|
// Move backtrace from body to header
|
hops = 1;
|
for (;;) {
|
bool end;
|
|
if (hops > ttl) {
|
// This isn't malformed, but it has gone
|
// through too many hops. Do not disconnect,
|
// because we can legitimately receive messages
|
// with too many hops from devices, etc.
|
goto drop;
|
}
|
hops++;
|
if (nni_msg_len(msg) < 4) {
|
// Peer is speaking garbage. Kick it.
|
nni_msg_free(msg);
|
nni_aio_set_msg(&p->aio_recv, NULL);
|
nni_pipe_close(p->pipe);
|
return;
|
}
|
body = nni_msg_body(msg);
|
end = ((body[0] & 0x80u) != 0);
|
if (nni_msg_header_append(msg, body, 4) != 0) {
|
// Out of memory, so drop it.
|
goto drop;
|
}
|
nni_msg_trim(msg, 4);
|
if (end) {
|
break;
|
}
|
}
|
|
len = nni_msg_header_len(msg);
|
|
nni_mtx_lock(&s->lk);
|
|
if (p->closed) {
|
// If we are closed, then we can't return data.
|
nni_aio_set_msg(&p->aio_recv, NULL);
|
nni_mtx_unlock(&s->lk);
|
nni_msg_free(msg);
|
return;
|
}
|
|
if ((ctx = nni_list_first(&s->recvq)) == NULL) {
|
// No one waiting to receive yet, holding pattern.
|
nni_list_append(&s->recvpipes, p);
|
nni_pollable_raise(&s->readable);
|
nni_mtx_unlock(&s->lk);
|
return;
|
}
|
|
nni_list_remove(&s->recvq, ctx);
|
aio = ctx->raio;
|
ctx->raio = NULL;
|
nni_aio_set_msg(&p->aio_recv, NULL);
|
if ((ctx == &s->ctx) && !p->busy) {
|
nni_pollable_raise(&s->writable);
|
}
|
|
// schedule another receive
|
nni_pipe_recv(p->pipe, &p->aio_recv);
|
|
ctx->btrace_len = len;
|
memcpy(ctx->btrace, nni_msg_header(msg), len);
|
nni_msg_header_clear(msg);
|
ctx->pipe_id = p->id;
|
|
nni_mtx_unlock(&s->lk);
|
|
nni_aio_set_msg(aio, msg);
|
nni_aio_finish_sync(aio, 0, nni_msg_len(msg));
|
return;
|
|
drop:
|
nni_msg_free(msg);
|
nni_aio_set_msg(&p->aio_recv, NULL);
|
nni_pipe_recv(p->pipe, &p->aio_recv);
|
}
|
|
static int
|
rep0_sock_set_max_ttl(void *arg, const void *buf, size_t sz, nni_opt_type t)
|
{
|
rep0_sock *s = arg;
|
int ttl;
|
int rv;
|
|
if ((rv = nni_copyin_int(&ttl, buf, sz, 1, NNI_MAX_MAX_TTL, t)) == 0) {
|
nni_atomic_set(&s->ttl, ttl);
|
}
|
return (rv);
|
}
|
|
static int
|
rep0_sock_get_max_ttl(void *arg, void *buf, size_t *szp, nni_opt_type t)
|
{
|
rep0_sock *s = arg;
|
|
return (nni_copyout_int(nni_atomic_get(&s->ttl), buf, szp, t));
|
}
|
|
static int
|
rep0_sock_get_sendfd(void *arg, void *buf, size_t *szp, nni_opt_type t)
|
{
|
rep0_sock *s = arg;
|
int rv;
|
int fd;
|
|
if ((rv = nni_pollable_getfd(&s->writable, &fd)) != 0) {
|
return (rv);
|
}
|
return (nni_copyout_int(fd, buf, szp, t));
|
}
|
|
static int
|
rep0_sock_get_recvfd(void *arg, void *buf, size_t *szp, nni_opt_type t)
|
{
|
rep0_sock *s = arg;
|
int rv;
|
int fd;
|
|
if ((rv = nni_pollable_getfd(&s->readable, &fd)) != 0) {
|
return (rv);
|
}
|
|
return (nni_copyout_int(fd, buf, szp, t));
|
}
|
|
static void
|
rep0_sock_send(void *arg, nni_aio *aio)
|
{
|
rep0_sock *s = arg;
|
|
rep0_ctx_send(&s->ctx, aio);
|
}
|
|
static void
|
rep0_sock_recv(void *arg, nni_aio *aio)
|
{
|
rep0_sock *s = arg;
|
|
rep0_ctx_recv(&s->ctx, aio);
|
}
|
|
// This is the global protocol structure -- our linkage to the core.
|
// This should be the only global non-static symbol in this file.
|
static nni_proto_pipe_ops rep0_pipe_ops = {
|
.pipe_size = sizeof(rep0_pipe),
|
.pipe_init = rep0_pipe_init,
|
.pipe_fini = rep0_pipe_fini,
|
.pipe_start = rep0_pipe_start,
|
.pipe_close = rep0_pipe_close,
|
.pipe_stop = rep0_pipe_stop,
|
};
|
|
static nni_proto_ctx_ops rep0_ctx_ops = {
|
.ctx_size = sizeof(rep0_ctx),
|
.ctx_init = rep0_ctx_init,
|
.ctx_fini = rep0_ctx_fini,
|
.ctx_send = rep0_ctx_send,
|
.ctx_recv = rep0_ctx_recv,
|
};
|
|
static nni_option rep0_sock_options[] = {
|
{
|
.o_name = NNG_OPT_MAXTTL,
|
.o_get = rep0_sock_get_max_ttl,
|
.o_set = rep0_sock_set_max_ttl,
|
},
|
{
|
.o_name = NNG_OPT_RECVFD,
|
.o_get = rep0_sock_get_recvfd,
|
},
|
{
|
.o_name = NNG_OPT_SENDFD,
|
.o_get = rep0_sock_get_sendfd,
|
},
|
// terminate list
|
{
|
.o_name = NULL,
|
},
|
};
|
|
static nni_proto_sock_ops rep0_sock_ops = {
|
.sock_size = sizeof(rep0_sock),
|
.sock_init = rep0_sock_init,
|
.sock_fini = rep0_sock_fini,
|
.sock_open = rep0_sock_open,
|
.sock_close = rep0_sock_close,
|
.sock_options = rep0_sock_options,
|
.sock_send = rep0_sock_send,
|
.sock_recv = rep0_sock_recv,
|
};
|
|
static nni_proto rep0_proto = {
|
.proto_version = NNI_PROTOCOL_VERSION,
|
.proto_self = { NNG_REP0_SELF, NNG_REP0_SELF_NAME },
|
.proto_peer = { NNG_REP0_PEER, NNG_REP0_PEER_NAME },
|
.proto_flags = NNI_PROTO_FLAG_SNDRCV,
|
.proto_sock_ops = &rep0_sock_ops,
|
.proto_pipe_ops = &rep0_pipe_ops,
|
.proto_ctx_ops = &rep0_ctx_ops,
|
};
|
|
int
|
nng_rep0_open(nng_socket *sidp)
|
{
|
return (nni_proto_open(sidp, &rep0_proto));
|
}
|
