view src/http/modules/ngx_http_chunked_filter_module.c @ 7966:5d09596909c6 stable-1.20

Upstream: fixed timeouts with gRPC, SSL and select (ticket #2229). With SSL it is possible that an established connection is ready for reading after the handshake. Further, events might be already disabled in case of level-triggered event methods. If this happens and ngx_http_upstream_send_request() blocks waiting for some data from the upstream, such as flow control in case of gRPC, the connection will time out due to no read events on the upstream connection. Fix is to explicitly check the c->read->ready flag if sending request blocks and post a read event if it is set. Note that while it is possible to modify ngx_ssl_handshake() to keep read events active, this won't completely resolve the issue, since there can be data already received during the SSL handshake (see 573bd30e46b4).
author Maxim Dounin <mdounin@mdounin.ru>
date Fri, 20 Aug 2021 03:53:56 +0300
parents 1b068a4e82d8
children 46e3542d51b3
line wrap: on
line source


/*
 * Copyright (C) Igor Sysoev
 * Copyright (C) Nginx, Inc.
 */


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


typedef struct {
    ngx_chain_t         *free;
    ngx_chain_t         *busy;
} ngx_http_chunked_filter_ctx_t;


static ngx_int_t ngx_http_chunked_filter_init(ngx_conf_t *cf);
static ngx_chain_t *ngx_http_chunked_create_trailers(ngx_http_request_t *r,
    ngx_http_chunked_filter_ctx_t *ctx);


static ngx_http_module_t  ngx_http_chunked_filter_module_ctx = {
    NULL,                                  /* preconfiguration */
    ngx_http_chunked_filter_init,          /* postconfiguration */

    NULL,                                  /* create main configuration */
    NULL,                                  /* init main configuration */

    NULL,                                  /* create server configuration */
    NULL,                                  /* merge server configuration */

    NULL,                                  /* create location configuration */
    NULL                                   /* merge location configuration */
};


ngx_module_t  ngx_http_chunked_filter_module = {
    NGX_MODULE_V1,
    &ngx_http_chunked_filter_module_ctx,   /* module context */
    NULL,                                  /* module directives */
    NGX_HTTP_MODULE,                       /* module type */
    NULL,                                  /* init master */
    NULL,                                  /* init module */
    NULL,                                  /* init process */
    NULL,                                  /* init thread */
    NULL,                                  /* exit thread */
    NULL,                                  /* exit process */
    NULL,                                  /* exit master */
    NGX_MODULE_V1_PADDING
};


static ngx_http_output_header_filter_pt  ngx_http_next_header_filter;
static ngx_http_output_body_filter_pt    ngx_http_next_body_filter;


static ngx_int_t
ngx_http_chunked_header_filter(ngx_http_request_t *r)
{
    ngx_http_core_loc_conf_t       *clcf;
    ngx_http_chunked_filter_ctx_t  *ctx;

    if (r->headers_out.status == NGX_HTTP_NOT_MODIFIED
        || r->headers_out.status == NGX_HTTP_NO_CONTENT
        || r->headers_out.status < NGX_HTTP_OK
        || r != r->main
        || r->method == NGX_HTTP_HEAD)
    {
        return ngx_http_next_header_filter(r);
    }

    if (r->headers_out.content_length_n == -1
        || r->expect_trailers)
    {
        clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);

        if (r->http_version >= NGX_HTTP_VERSION_11
            && clcf->chunked_transfer_encoding)
        {
            if (r->expect_trailers) {
                ngx_http_clear_content_length(r);
            }

            r->chunked = 1;

            ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_chunked_filter_ctx_t));
            if (ctx == NULL) {
                return NGX_ERROR;
            }

            ngx_http_set_ctx(r, ctx, ngx_http_chunked_filter_module);

        } else if (r->headers_out.content_length_n == -1) {
            r->keepalive = 0;
        }
    }

    return ngx_http_next_header_filter(r);
}


static ngx_int_t
ngx_http_chunked_body_filter(ngx_http_request_t *r, ngx_chain_t *in)
{
    u_char                         *chunk;
    off_t                           size;
    ngx_int_t                       rc;
    ngx_buf_t                      *b;
    ngx_chain_t                    *out, *cl, *tl, **ll;
    ngx_http_chunked_filter_ctx_t  *ctx;

    if (in == NULL || !r->chunked || r->header_only) {
        return ngx_http_next_body_filter(r, in);
    }

    ctx = ngx_http_get_module_ctx(r, ngx_http_chunked_filter_module);

    out = NULL;
    ll = &out;

    size = 0;
    cl = in;

    for ( ;; ) {
        ngx_log_debug1(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http chunk: %O", ngx_buf_size(cl->buf));

        size += ngx_buf_size(cl->buf);

        if (cl->buf->flush
            || cl->buf->sync
            || ngx_buf_in_memory(cl->buf)
            || cl->buf->in_file)
        {
            tl = ngx_alloc_chain_link(r->pool);
            if (tl == NULL) {
                return NGX_ERROR;
            }

            tl->buf = cl->buf;
            *ll = tl;
            ll = &tl->next;
        }

        if (cl->next == NULL) {
            break;
        }

        cl = cl->next;
    }

    if (size) {
        tl = ngx_chain_get_free_buf(r->pool, &ctx->free);
        if (tl == NULL) {
            return NGX_ERROR;
        }

        b = tl->buf;
        chunk = b->start;

        if (chunk == NULL) {
            /* the "0000000000000000" is 64-bit hexadecimal string */

            chunk = ngx_palloc(r->pool, sizeof("0000000000000000" CRLF) - 1);
            if (chunk == NULL) {
                return NGX_ERROR;
            }

            b->start = chunk;
            b->end = chunk + sizeof("0000000000000000" CRLF) - 1;
        }

        b->tag = (ngx_buf_tag_t) &ngx_http_chunked_filter_module;
        b->memory = 0;
        b->temporary = 1;
        b->pos = chunk;
        b->last = ngx_sprintf(chunk, "%xO" CRLF, size);

        tl->next = out;
        out = tl;
    }

    if (cl->buf->last_buf) {
        tl = ngx_http_chunked_create_trailers(r, ctx);
        if (tl == NULL) {
            return NGX_ERROR;
        }

        cl->buf->last_buf = 0;

        *ll = tl;

        if (size == 0) {
            tl->buf->pos += 2;
        }

    } else if (size > 0) {
        tl = ngx_chain_get_free_buf(r->pool, &ctx->free);
        if (tl == NULL) {
            return NGX_ERROR;
        }

        b = tl->buf;

        b->tag = (ngx_buf_tag_t) &ngx_http_chunked_filter_module;
        b->temporary = 0;
        b->memory = 1;
        b->pos = (u_char *) CRLF;
        b->last = b->pos + 2;

        *ll = tl;

    } else {
        *ll = NULL;
    }

    rc = ngx_http_next_body_filter(r, out);

    ngx_chain_update_chains(r->pool, &ctx->free, &ctx->busy, &out,
                            (ngx_buf_tag_t) &ngx_http_chunked_filter_module);

    return rc;
}


static ngx_chain_t *
ngx_http_chunked_create_trailers(ngx_http_request_t *r,
    ngx_http_chunked_filter_ctx_t *ctx)
{
    size_t            len;
    ngx_buf_t        *b;
    ngx_uint_t        i;
    ngx_chain_t      *cl;
    ngx_list_part_t  *part;
    ngx_table_elt_t  *header;

    len = 0;

    part = &r->headers_out.trailers.part;
    header = part->elts;

    for (i = 0; /* void */; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }

            part = part->next;
            header = part->elts;
            i = 0;
        }

        if (header[i].hash == 0) {
            continue;
        }

        len += header[i].key.len + sizeof(": ") - 1
               + header[i].value.len + sizeof(CRLF) - 1;
    }

    cl = ngx_chain_get_free_buf(r->pool, &ctx->free);
    if (cl == NULL) {
        return NULL;
    }

    b = cl->buf;

    b->tag = (ngx_buf_tag_t) &ngx_http_chunked_filter_module;
    b->temporary = 0;
    b->memory = 1;
    b->last_buf = 1;

    if (len == 0) {
        b->pos = (u_char *) CRLF "0" CRLF CRLF;
        b->last = b->pos + sizeof(CRLF "0" CRLF CRLF) - 1;
        return cl;
    }

    len += sizeof(CRLF "0" CRLF CRLF) - 1;

    b->pos = ngx_palloc(r->pool, len);
    if (b->pos == NULL) {
        return NULL;
    }

    b->last = b->pos;

    *b->last++ = CR; *b->last++ = LF;
    *b->last++ = '0';
    *b->last++ = CR; *b->last++ = LF;

    part = &r->headers_out.trailers.part;
    header = part->elts;

    for (i = 0; /* void */; i++) {

        if (i >= part->nelts) {
            if (part->next == NULL) {
                break;
            }

            part = part->next;
            header = part->elts;
            i = 0;
        }

        if (header[i].hash == 0) {
            continue;
        }

        ngx_log_debug2(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
                       "http trailer: \"%V: %V\"",
                       &header[i].key, &header[i].value);

        b->last = ngx_copy(b->last, header[i].key.data, header[i].key.len);
        *b->last++ = ':'; *b->last++ = ' ';

        b->last = ngx_copy(b->last, header[i].value.data, header[i].value.len);
        *b->last++ = CR; *b->last++ = LF;
    }

    *b->last++ = CR; *b->last++ = LF;

    return cl;
}


static ngx_int_t
ngx_http_chunked_filter_init(ngx_conf_t *cf)
{
    ngx_http_next_header_filter = ngx_http_top_header_filter;
    ngx_http_top_header_filter = ngx_http_chunked_header_filter;

    ngx_http_next_body_filter = ngx_http_top_body_filter;
    ngx_http_top_body_filter = ngx_http_chunked_body_filter;

    return NGX_OK;
}