view src/os/unix/ngx_send.c @ 7892:2096b21fcd10

gRPC: RST_STREAM(NO_ERROR) handling (ticket #1792). As per https://tools.ietf.org/html/rfc7540#section-8.1, : A server can send a complete response prior to the client : sending an entire request if the response does not depend on : any portion of the request that has not been sent and : received. When this is true, a server MAY request that the : client abort transmission of a request without error by : sending a RST_STREAM with an error code of NO_ERROR after : sending a complete response (i.e., a frame with the : END_STREAM flag). Clients MUST NOT discard responses as a : result of receiving such a RST_STREAM, though clients can : always discard responses at their discretion for other : reasons. Previously, RST_STREAM(NO_ERROR) received from upstream after a frame with the END_STREAM flag was incorrectly treated as an error. Now, a single RST_STREAM(NO_ERROR) is properly handled. This fixes problems observed with modern grpc-c [1], as well as with the Go gRPC module. [1] https://github.com/grpc/grpc/pull/1661
author Ruslan Ermilov <ru@nginx.com>
date Thu, 23 Apr 2020 15:10:24 +0300
parents f01ab2dbcfdc
children
line wrap: on
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/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


#include <ngx_config.h>
#include <ngx_core.h>
#include <ngx_event.h>


ssize_t
ngx_unix_send(ngx_connection_t *c, u_char *buf, size_t size)
{
    ssize_t       n;
    ngx_err_t     err;
    ngx_event_t  *wev;

    wev = c->write;

#if (NGX_HAVE_KQUEUE)

    if ((ngx_event_flags & NGX_USE_KQUEUE_EVENT) && wev->pending_eof) {
        (void) ngx_connection_error(c, wev->kq_errno,
                               "kevent() reported about an closed connection");
        wev->error = 1;
        return NGX_ERROR;
    }

#endif

    for ( ;; ) {
        n = send(c->fd, buf, size, 0);

        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, c->log, 0,
                       "send: fd:%d %z of %uz", c->fd, n, size);

        if (n > 0) {
            if (n < (ssize_t) size) {
                wev->ready = 0;
            }

            c->sent += n;

            return n;
        }

        err = ngx_socket_errno;

        if (n == 0) {
            ngx_log_error(NGX_LOG_ALERT, c->log, err, "send() returned zero");
            wev->ready = 0;
            return n;
        }

        if (err == NGX_EAGAIN || err == NGX_EINTR) {
            wev->ready = 0;

            ngx_log_debug0(NGX_LOG_DEBUG_EVENT, c->log, err,
                           "send() not ready");

            if (err == NGX_EAGAIN) {
                return NGX_AGAIN;
            }

        } else {
            wev->error = 1;
            (void) ngx_connection_error(c, err, "send() failed");
            return NGX_ERROR;
        }
    }
}