# HG changeset patch
# User Piotr Sikora <piotrsikora@google.com>
# Date 1466735480 25200
# Thu Jun 23 19:31:20 2016 -0700
# Node ID a96187a9806536ab2a8bf3fa7f7b659cf5d3ff13
# Parent 6f69e3c0f780e29bca752fc1f938f4a459a1ec59
HTTP: add support for trailers in HTTP responses.

Example:

ngx_table_elt_t *h;

h = ngx_list_push(&r->headers_out.trailers);
if (h == NULL) {
return NGX_ERROR;
}

ngx_str_set(&h->key, "Fun");
ngx_str_set(&h->value, "with trailers");
h->hash = ngx_hash_key_lc(h->key.data, h->key.len);

The code above adds "Fun: with trailers" trailer to the response to
the request with "TE: trailers" header (which indicates support for
trailers).

Note that trailers MUST be added before last buffer of the response
(last_buf = 1) reaches chunked or v2 output filters, otherwise they
are going to be ignored.

Signed-off-by: Piotr Sikora <piotrsikora@google.com>

diff -r 6f69e3c0f780 -r a96187a98065 src/http/modules/ngx_http_chunked_filter_module.c
--- a/src/http/modules/ngx_http_chunked_filter_module.c
+++ b/src/http/modules/ngx_http_chunked_filter_module.c
@@ -17,6 +17,7 @@ typedef struct {


static ngx_int_t ngx_http_chunked_filter_init(ngx_conf_t *cf);
+static ngx_chain_t *ngx_http_chunked_get_trailers(ngx_http_request_t *r);


static ngx_http_module_t ngx_http_chunked_filter_module_ctx = {
@@ -69,28 +70,31 @@ ngx_http_chunked_header_filter(ngx_http_
return ngx_http_next_header_filter(r);
}

- if (r->headers_out.content_length_n == -1) {
+ clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+
+ if (clcf->chunked_transfer_encoding && r->trailers_ok) {
+ ngx_http_clear_content_length(r);
+ r->chunked = 1;
+
+ } else if (r->headers_out.content_length_n == -1) {
if (r->http_version < NGX_HTTP_VERSION_11) {
r->keepalive = 0;

+ } else if (clcf->chunked_transfer_encoding) {
+ r->chunked = 1;
+
} else {
- clcf = ngx_http_get_module_loc_conf(r, ngx_http_core_module);
+ r->keepalive = 0;
+ }
+ }

- if (clcf->chunked_transfer_encoding) {
- r->chunked = 1;
+ if (r->chunked) {
+ ctx = ngx_pcalloc(r->pool, sizeof(ngx_http_chunked_filter_ctx_t));
+ if (ctx == NULL) {
+ return NGX_ERROR;
+ }

- 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 {
- r->keepalive = 0;
- }
- }
+ ngx_http_set_ctx(r, ctx, ngx_http_chunked_filter_module);
}

return ngx_http_next_header_filter(r);
@@ -201,6 +205,15 @@ ngx_http_chunked_body_filter(ngx_http_re
b->pos += 2;
}

+ if (r->trailers_ok) {
+ tl->next = ngx_http_chunked_get_trailers(r);
+
+ if (tl->next != NULL) {
+ b->last -= 2;
+ b->last_buf = 0;
+ }
+ }
+
} else if (size > 0) {
tl = ngx_chain_get_free_buf(r->pool, &ctx->free);
if (tl == NULL) {
@@ -230,6 +243,108 @@ ngx_http_chunked_body_filter(ngx_http_re
}


+static ngx_chain_t *
+ngx_http_chunked_get_trailers(ngx_http_request_t *r)
+{
+ 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;
+ ngx_http_chunked_filter_ctx_t *ctx;
+
+ 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;
+ }
+
+ if (len == 0) {
+ return NULL;
+ }
+
+ len += sizeof(CRLF) - 1;
+
+ ctx = ngx_http_get_module_ctx(r, ngx_http_chunked_filter_module);
+
+ 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;
+
+ b->start = ngx_palloc(r->pool, len);
+ if (b->start == NULL) {
+ return NULL;
+ }
+
+ b->end = b->last + len;
+ b->pos = b->start;
+ b->last = b->start;
+
+ 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;
+ }
+
+ /* the end of HTTP trailer */
+ *b->last++ = CR; *b->last++ = LF;
+
+ return cl;
+}
+
+
static ngx_int_t
ngx_http_chunked_filter_init(ngx_conf_t *cf)
{
diff -r 6f69e3c0f780 -r a96187a98065 src/http/ngx_http_request.c
--- a/src/http/ngx_http_request.c
+++ b/src/http/ngx_http_request.c
@@ -29,6 +29,8 @@ static ngx_int_t ngx_http_process_connec
ngx_table_elt_t *h, ngx_uint_t offset);
static ngx_int_t ngx_http_process_user_agent(ngx_http_request_t *r,
ngx_table_elt_t *h, ngx_uint_t offset);
+static ngx_int_t ngx_http_process_te(ngx_http_request_t *r,
+ ngx_table_elt_t *h, ngx_uint_t offset);

static ngx_int_t ngx_http_validate_host(ngx_str_t *host, ngx_pool_t *pool,
ngx_uint_t alloc);
@@ -125,6 +127,10 @@ ngx_http_header_t ngx_http_headers_in[]
offsetof(ngx_http_headers_in_t, if_range),
ngx_http_process_unique_header_line },

+ { ngx_string("TE"),
+ offsetof(ngx_http_headers_in_t, te),
+ ngx_http_process_te },
+
{ ngx_string("Transfer-Encoding"),
offsetof(ngx_http_headers_in_t, transfer_encoding),
ngx_http_process_header_line },
@@ -559,6 +565,14 @@ ngx_http_create_request(ngx_connection_t
return NULL;
}

+ if (ngx_list_init(&r->headers_out.trailers, r->pool, 4,
+ sizeof(ngx_table_elt_t))
+ != NGX_OK)
+ {
+ ngx_destroy_pool(r->pool);
+ return NULL;
+ }
+
r->ctx = ngx_pcalloc(r->pool, sizeof(void *) * ngx_http_max_module);
if (r->ctx == NULL) {
ngx_destroy_pool(r->pool);
@@ -1737,6 +1751,59 @@ ngx_http_process_user_agent(ngx_http_req


static ngx_int_t
+ngx_http_process_te(ngx_http_request_t *r, ngx_table_elt_t *h,
+ ngx_uint_t offset)
+{
+ u_char *p;
+
+ if (ngx_http_process_multi_header_lines(r, h, offset) != NGX_OK) {
+ return NGX_ERROR;
+ }
+
+ if (r->http_version < NGX_HTTP_VERSION_11) {
+ return NGX_OK;
+ }
+
+ if (h->value.len == sizeof("trailers") - 1
+ && ngx_memcmp(h->value.data, "trailers", sizeof("trailers") - 1) == 0)
+ {
+ r->trailers_ok = 1;
+ return NGX_OK;
+ }
+
+ if (r->http_version >= NGX_HTTP_VERSION_20) {
+ ngx_log_error(NGX_LOG_INFO, r->connection->log, 0,
+ "client sent HTTP/2 request with invalid value \"%V\" "
+ "in \"TE\" header", &h->value);
+
+ ngx_http_finalize_request(r, NGX_HTTP_BAD_REQUEST);
+ return NGX_ERROR;
+ }
+
+ if (h->value.len < sizeof("trailers") - 1) {
+ return NGX_OK;
+ }
+
+ p = ngx_strcasestrn(h->value.data, "trailers", sizeof("trailers") - 2);
+ if (p == NULL) {
+ return NGX_OK;
+ }
+
+ if (p == h->value.data || *(p - 1) == ',' || *(p - 1) == ' ') {
+
+ p += sizeof("trailers") - 1;
+
+ if (p == h->value.data + h->value.len || *p == ',' || *p == ' ') {
+ r->trailers_ok = 1;
+ return NGX_OK;
+ }
+ }
+
+ return NGX_OK;
+}
+
+
+static ngx_int_t
ngx_http_process_multi_header_lines(ngx_http_request_t *r, ngx_table_elt_t *h,
ngx_uint_t offset)
{
diff -r 6f69e3c0f780 -r a96187a98065 src/http/ngx_http_request.h
--- a/src/http/ngx_http_request.h
+++ b/src/http/ngx_http_request.h
@@ -189,6 +189,7 @@ typedef struct {
ngx_table_elt_t *range;
ngx_table_elt_t *if_range;

+ ngx_array_t te;
ngx_table_elt_t *transfer_encoding;
ngx_table_elt_t *expect;
ngx_table_elt_t *upgrade;
@@ -245,6 +246,7 @@ typedef struct {

typedef struct {
ngx_list_t headers;
+ ngx_list_t trailers;

ngx_uint_t status;
ngx_str_t status_line;
@@ -514,6 +516,7 @@ struct ngx_http_request_s {
unsigned pipeline:1;
unsigned chunked:1;
unsigned header_only:1;
+ unsigned trailers_ok:1;
unsigned keepalive:1;
unsigned lingering_close:1;
unsigned discard_body:1;
diff -r 6f69e3c0f780 -r a96187a98065 src/http/v2/ngx_http_v2_filter_module.c
--- a/src/http/v2/ngx_http_v2_filter_module.c
+++ b/src/http/v2/ngx_http_v2_filter_module.c
@@ -56,7 +56,9 @@ static u_char *ngx_http_v2_string_encode
static u_char *ngx_http_v2_write_int(u_char *pos, ngx_uint_t prefix,
ngx_uint_t value);
static ngx_http_v2_out_frame_t *ngx_http_v2_create_headers_frame(
- ngx_http_request_t *r, u_char *pos, u_char *end);
+ ngx_http_request_t *r, u_char *pos, u_char *end, ngx_uint_t fin);
+static ngx_http_v2_out_frame_t *ngx_http_v2_create_trailers_frame(
+ ngx_http_request_t *r);

static ngx_chain_t *ngx_http_v2_send_chain(ngx_connection_t *fc,
ngx_chain_t *in, off_t limit);
@@ -571,7 +573,7 @@ ngx_http_v2_header_filter(ngx_http_reque
header[i].value.len, tmp);
}

- frame = ngx_http_v2_create_headers_frame(r, start, pos);
+ frame = ngx_http_v2_create_headers_frame(r, start, pos, r->header_only);
if (frame == NULL) {
return NGX_ERROR;
}
@@ -595,6 +597,121 @@ ngx_http_v2_header_filter(ngx_http_reque
}


+static ngx_http_v2_out_frame_t *
+ngx_http_v2_create_trailers_frame(ngx_http_request_t *r)
+{
+ u_char *pos, *start, *tmp;
+ size_t len, tmp_len;
+ ngx_uint_t i;
+ ngx_list_part_t *part;
+ ngx_table_elt_t *header;
+
+ len = 0;
+ tmp_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;
+ }
+
+ if (header[i].key.len > NGX_HTTP_V2_MAX_FIELD) {
+ ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
+ "ignoring too long response trailer name: \"%V\"",
+ &header[i].key);
+ continue;
+ }
+
+ if (header[i].value.len > NGX_HTTP_V2_MAX_FIELD) {
+ ngx_log_error(NGX_LOG_WARN, r->connection->log, 0,
+ "ignoring too long response trailer value: "
+ "\"%V: %V\"", &header[i].key, &header[i].value);
+ continue;
+ }
+
+ len += 1 + NGX_HTTP_V2_INT_OCTETS + header[i].key.len
+ + NGX_HTTP_V2_INT_OCTETS + header[i].value.len;
+
+ if (header[i].key.len > tmp_len) {
+ tmp_len = header[i].key.len;
+ }
+
+ if (header[i].value.len > tmp_len) {
+ tmp_len = header[i].value.len;
+ }
+ }
+
+ if (len == 0) {
+ return NULL;
+ }
+
+ tmp = ngx_palloc(r->pool, tmp_len);
+ pos = ngx_pnalloc(r->pool, len);
+
+ if (pos == NULL || tmp == NULL) {
+ return NULL;
+ }
+
+ start = pos;
+
+ 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
+ || header[i].key.len > NGX_HTTP_V2_MAX_FIELD
+ || header[i].value.len > NGX_HTTP_V2_MAX_FIELD)
+ {
+ continue;
+ }
+
+#if (NGX_DEBUG)
+ if (r->connection->log->log_level & NGX_LOG_DEBUG_HTTP) {
+ ngx_strlow(tmp, header[i].key.data, header[i].key.len);
+
+ ngx_log_debug3(NGX_LOG_DEBUG_HTTP, r->connection->log, 0,
+ "http2 output trailer: \"%*s: %V\"",
+ header[i].key.len, tmp, &header[i].value);
+ }
+#endif
+
+ *pos++ = 0;
+
+ pos = ngx_http_v2_write_name(pos, header[i].key.data,
+ header[i].key.len, tmp);
+
+ pos = ngx_http_v2_write_value(pos, header[i].value.data,
+ header[i].value.len, tmp);
+ }
+
+ return ngx_http_v2_create_headers_frame(r, start, pos, 1);
+}
+
+
static u_char *
ngx_http_v2_string_encode(u_char *dst, u_char *src, size_t len, u_char *tmp,
ngx_uint_t lower)
@@ -645,7 +762,7 @@ ngx_http_v2_write_int(u_char *pos, ngx_u

static ngx_http_v2_out_frame_t *
ngx_http_v2_create_headers_frame(ngx_http_request_t *r, u_char *pos,
- u_char *end)
+ u_char *end, ngx_uint_t fin)
{
u_char type, flags;
size_t rest, frame_size;
@@ -666,12 +783,12 @@ ngx_http_v2_create_headers_frame(ngx_htt
frame->stream = stream;
frame->length = rest;
frame->blocked = 1;
- frame->fin = r->header_only;
+ frame->fin = fin;

ll = &frame->first;

type = NGX_HTTP_V2_HEADERS_FRAME;
- flags = r->header_only ? NGX_HTTP_V2_END_STREAM_FLAG : NGX_HTTP_V2_NO_FLAG;
+ flags = fin ? NGX_HTTP_V2_END_STREAM_FLAG : NGX_HTTP_V2_NO_FLAG;
frame_size = stream->connection->frame_size;

for ( ;; ) {
@@ -733,7 +850,7 @@ ngx_http_v2_create_headers_frame(ngx_htt
continue;
}

- b->last_buf = r->header_only;
+ b->last_buf = fin;
cl->next = NULL;
frame->last = cl;

@@ -755,7 +872,7 @@ ngx_http_v2_send_chain(ngx_connection_t
ngx_http_request_t *r;
ngx_http_v2_stream_t *stream;
ngx_http_v2_loc_conf_t *h2lcf;
- ngx_http_v2_out_frame_t *frame;
+ ngx_http_v2_out_frame_t *frame, *trailers;
ngx_http_v2_connection_t *h2c;

r = fc->data;
@@ -829,6 +946,8 @@ ngx_http_v2_send_chain(ngx_connection_t
frame_size = (h2lcf->chunk_size < h2c->frame_size)
? h2lcf->chunk_size : h2c->frame_size;

+ trailers = NULL;
+
#if (NGX_SUPPRESS_WARN)
cl = NULL;
#endif
@@ -891,6 +1010,13 @@ ngx_http_v2_send_chain(ngx_connection_t
size -= rest;
}

+ if (cl->buf->last_buf && r->trailers_ok) {
+ trailers = ngx_http_v2_create_trailers_frame(r);
+ if (trailers) {
+ cl->buf->last_buf = 0;
+ }
+ }
+
frame = ngx_http_v2_filter_get_data_frame(stream, frame_size, out, cl);
if (frame == NULL) {
return NGX_CHAIN_ERROR;
@@ -903,6 +1029,11 @@ ngx_http_v2_send_chain(ngx_connection_t
stream->send_window -= frame_size;
stream->queued++;

+ if (trailers) {
+ ngx_http_v2_queue_frame(h2c, trailers);
+ stream->queued++;
+ }
+
if (in == NULL) {
break;
}

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