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MEDIUM: h2: add a function to emit an HTTP/1 request from a headers list

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The current H2 to H1 protocol conversion presents some issues which will
require to perform some processing on certain headers before writing them
so it's not possible to convert HPACK to H1 on the fly.

Here we introduce a function which performs half of what hpack_decode_header()
used to do, which is to take a list of headers on input and emit the
corresponding request in HTTP/1.1 format. The code is the same and functions
were renamed to be prefixed with "h2" instead of "hpack", though it ends
up being simpler as the various HPACK-specific cases could be fused into
a single one (ie: add header).

Moving this part here makes a lot of sense as now this code is specific to
what is documented in HTTP/2 RFC 7540 and will be able to deal with special
cases related to H2 to H1 conversion enumerated in section 8.1.

Various error codes which were previously assigned to HPACK were never
used (aside being negative) and were all replaced by -1 with a comment
indicating what error was detected. The code could be further factored
thanks to this but this commit focuses on compatibility first.

This code is not yet used but builds fine.
This commit is contained in:
Willy Tarreau 2017-11-21 19:55:27 +01:00
parent 8f650c369d
commit f24ea8e45e
3 changed files with 304 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
Makefile
View File

@ -867,7 +867,7 @@ OBJS = src/cfgparse.o src/proto_http.o src/stats.o src/server.o src/stream.o \
src/regex.o src/queue.o src/frontend.o src/arg.o src/proto_uxst.o \
src/raw_sock.o src/lb_chash.o src/lb_fwlc.o src/lb_fwrr.o \
src/lb_fas.o src/applet.o src/hdr_idx.o src/ev_select.o src/hash.o \
src/lb_map.o src/base64.o src/sha1.o src/protocol.o src/h1.o \
src/lb_map.o src/base64.o src/sha1.o src/protocol.o src/h1.o src/h2.o \
src/action.o src/hathreads.o src/mux_pt.o src/cache.o src/shctx.o
EBTREE_OBJS = $(EBTREE_DIR)/ebtree.o $(EBTREE_DIR)/eb32sctree.o \

88
include/common/h2.h
View File

@ -5,27 +5,67 @@
* Copyright (C) 2000-2017 Willy Tarreau - w@1wt.eu
* Copyright (C) 2017 HAProxy Technologies
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#ifndef _COMMON_H2_H
#define _COMMON_H2_H
#include <common/config.h>
#include <common/http-hdr.h>
#include <common/ist.h>
/* indexes of most important pseudo headers can be simplified to an almost
* linear array by dividing the index by 2 for all values from 1 to 9, and
* caping to 4 for values up to 14 ; thus it fits in a single 24-bit array
* shifted by 3 times the index value/2, or a 32-bit array shifted by 4x.
* Don't change these values, they are assumed by hpack_idx_to_phdr(). There
* is an entry for the Host header field which is not a pseudo-header but
* needs to be tracked as we should only use :authority if it's absent.
*/
enum {
H2_PHDR_IDX_NONE = 0,
H2_PHDR_IDX_AUTH = 1, /* :authority = 1 */
H2_PHDR_IDX_METH = 2, /* :method = 2..3 */
H2_PHDR_IDX_PATH = 3, /* :path = 4..5 */
H2_PHDR_IDX_SCHM = 4, /* :scheme = 6..7 */
H2_PHDR_IDX_STAT = 5, /* :status = 8..14 */
H2_PHDR_IDX_HOST = 6, /* Host, never returned, just a place-holder */
H2_PHDR_NUM_ENTRIES /* must be last */
};
/* bit fields indicating the pseudo-headers found. It also covers the HOST
* header field as well as any non-pseudo-header field (NONE).
*/
enum {
H2_PHDR_FND_NONE = 1 << H2_PHDR_IDX_NONE, /* found a regular header */
H2_PHDR_FND_AUTH = 1 << H2_PHDR_IDX_AUTH,
H2_PHDR_FND_METH = 1 << H2_PHDR_IDX_METH,
H2_PHDR_FND_PATH = 1 << H2_PHDR_IDX_PATH,
H2_PHDR_FND_SCHM = 1 << H2_PHDR_IDX_SCHM,
H2_PHDR_FND_STAT = 1 << H2_PHDR_IDX_STAT,
H2_PHDR_FND_HOST = 1 << H2_PHDR_IDX_HOST,
};
/* frame types, from the standard */
enum h2_ft {
H2_FT_DATA = 0x00, // RFC7540 #6.1
@ -104,6 +144,11 @@ enum h2_err {
"\x54\x50\x2f\x32\x2e\x30\x0d\x0a" \
"\x0d\x0a\x53\x4d\x0d\x0a\x0d\x0a"
/* various protocol processing functions */
int h2_make_h1_request(struct http_hdr *list, char *out, int osize);
/*
* Some helpful debugging functions.
*/
@ -125,6 +170,27 @@ static inline const char *h2_ft_str(int type)
}
}
/* returns the pseudo-header <str> corresponds to among H2_PHDR_IDX_*, 0 if not a
* pseudo-header, or -1 if not a valid pseudo-header.
*/
static inline int h2_str_to_phdr(const struct ist str)
{
if (*str.ptr == ':') {
if (isteq(str, ist(":path"))) return H2_PHDR_IDX_PATH;
else if (isteq(str, ist(":method"))) return H2_PHDR_IDX_METH;
else if (isteq(str, ist(":scheme"))) return H2_PHDR_IDX_SCHM;
else if (isteq(str, ist(":status"))) return H2_PHDR_IDX_STAT;
else if (isteq(str, ist(":authority"))) return H2_PHDR_IDX_AUTH;
/* all other names starting with ':' */
return -1;
}
/* not a pseudo header */
return 0;
}
#endif /* _COMMON_H2_H */
/*

226
src/h2.c Normal file
View File

@ -0,0 +1,226 @@
/*
* HTTP/2 protocol processing
*
* Copyright 2017 Willy Tarreau <w@1wt.eu>
* Copyright (C) 2017 HAProxy Technologies
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
* OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*/
#include <stdint.h>
#include <common/config.h>
#include <common/h2.h>
#include <common/http-hdr.h>
#include <common/ist.h>
/* Prepare the request line into <*ptr> (stopping at <end>) from pseudo headers
* stored in <phdr[]>. <fields> indicates what was found so far. This should be
* called once at the detection of the first general header field or at the end
* of the request if no general header field was found yet. Returns 0 on success
* or a negative error code on failure.
*/
static int h2_prepare_h1_reqline(uint32_t fields, struct ist *phdr, char **ptr, char *end)
{
char *out = *ptr;
int uri_idx = H2_PHDR_IDX_PATH;
if ((fields & H2_PHDR_FND_METH) && isteq(phdr[H2_PHDR_IDX_METH], ist("CONNECT"))) {
/* RFC 7540 #8.2.6 regarding CONNECT: ":scheme" and ":path"
* MUST be omitted ; ":authority" contains the host and port
* to connect to.
*/
if (fields & H2_PHDR_FND_SCHM) {
/* scheme not allowed */
goto fail;
}
else if (fields & H2_PHDR_FND_PATH) {
/* path not allowed */
goto fail;
}
else if (!(fields & H2_PHDR_FND_AUTH)) {
/* missing authority */
goto fail;
}
// otherwise OK ; let's use the authority instead of the URI
uri_idx = H2_PHDR_IDX_AUTH;
}
else if ((fields & (H2_PHDR_FND_METH|H2_PHDR_FND_SCHM|H2_PHDR_FND_PATH)) !=
(H2_PHDR_FND_METH|H2_PHDR_FND_SCHM|H2_PHDR_FND_PATH)) {
/* RFC 7540 #8.1.2.3 : all requests MUST include exactly one
* valid value for the ":method", ":scheme" and ":path" phdr
* unless it is a CONNECT request.
*/
if (!(fields & H2_PHDR_FND_METH)) {
/* missing method */
goto fail;
}
else if (!(fields & H2_PHDR_FND_SCHM)) {
/* missing scheme */
goto fail;
}
else {
/* missing path */
goto fail;
}
}
if (out + phdr[uri_idx].len + 1 + phdr[uri_idx].len + 11 > end) {
/* too large */
goto fail;
}
memcpy(out, phdr[H2_PHDR_IDX_METH].ptr, phdr[H2_PHDR_IDX_METH].len);
out += phdr[H2_PHDR_IDX_METH].len;
*(out++) = ' ';
memcpy(out, phdr[uri_idx].ptr, phdr[uri_idx].len);
out += phdr[uri_idx].len;
memcpy(out, " HTTP/1.1\r\n", 11);
out += 11;
*ptr = out;
return 0;
fail:
return -1;
}
/* Takes an H2 request present in the headers list <list> terminated by a name
* being <NULL,0> and emits the equivalent HTTP/1.1 request according to the
* rules documented in RFC7540 #8.1.2. The output contents are emitted in <out>
* for a max of <osize> bytes, and the amount of bytes emitted is returned. In
* case of error, a negative error code is returned.
*
* The headers list <list> must be composed of :
* - n.name != NULL, n.len > 0 : literal header name
* - n.name == NULL, n.len > 0 : indexed pseudo header name number <n.len>
* among H2_PHDR_IDX_*
* - n.name ignored, n.len == 0 : end of list
* - in all cases except the end of list, v.name and v.len must designate a
* valid value.
*/
int h2_make_h1_request(struct http_hdr *list, char *out, int osize)
{
struct ist phdr_val[H2_PHDR_NUM_ENTRIES];
char *out_end = out + osize;
uint32_t fields; /* bit mask of H2_PHDR_FND_* */
uint32_t idx;
int phdr;
int ret;
fields = 0;
for (idx = 0; list[idx].n.len != 0; idx++) {
if (!list[idx].n.ptr) {
/* this is an indexed pseudo-header */
phdr = list[idx].n.len;
}
else {
/* this can be any type of header */
phdr = h2_str_to_phdr(list[idx].n);
}
if (phdr > 0 && phdr < H2_PHDR_NUM_ENTRIES) {
/* insert a pseudo header by its index (in phdr) and value (in value) */
if (fields & ((1 << phdr) | H2_PHDR_FND_NONE)) {
if (fields & H2_PHDR_FND_NONE) {
/* pseudo header field after regular headers */
goto fail;
}
else {
/* repeated pseudo header field */
goto fail;
}
}
fields |= 1 << phdr;
phdr_val[phdr] = list[idx].v;
continue;
}
else if (phdr != 0) {
/* invalid pseudo header -- should never happen here */
goto fail;
}
/* regular header field in (name,value) */
if (!(fields & H2_PHDR_FND_NONE)) {
/* no more pseudo-headers, time to build the request line */
ret = h2_prepare_h1_reqline(fields, phdr_val, &out, out_end);
if (ret != 0)
goto leave;
fields |= H2_PHDR_FND_NONE;
}
if (isteq(list[idx].n, ist("host")))
fields |= H2_PHDR_FND_HOST;
if (out + list[idx].n.len + 2 + list[idx].v.len + 2 > out_end) {
/* too large */
goto fail;
}
/* copy "name: value" */
memcpy(out, list[idx].n.ptr, list[idx].n.len);
out += list[idx].n.len;
*(out++) = ':';
*(out++) = ' ';
memcpy(out, list[idx].v.ptr, list[idx].v.len);
out += list[idx].v.len;
*(out++) = '\r';
*(out++) = '\n';
}
/* Let's dump the request now if not yet emitted. */
if (!(fields & H2_PHDR_FND_NONE)) {
ret = h2_prepare_h1_reqline(fields, phdr_val, &out, out_end);
if (ret != 0)
goto leave;
}
/* complete with missing Host if needed */
if ((fields & (H2_PHDR_FND_HOST|H2_PHDR_FND_AUTH)) == H2_PHDR_FND_AUTH) {
/* missing Host field, use :authority instead */
if (out + 6 + phdr_val[H2_PHDR_IDX_AUTH].len + 2 > out_end) {
/* too large */
goto fail;
}
memcpy(out, "host: ", 6);
memcpy(out + 6, phdr_val[H2_PHDR_IDX_AUTH].ptr, phdr_val[H2_PHDR_IDX_AUTH].len);
out += 6 + phdr_val[H2_PHDR_IDX_AUTH].len;
*(out++) = '\r';
*(out++) = '\n';
}
/* And finish */
if (out + 2 > out_end) {
/* too large */
goto fail;
}
*(out++) = '\r';
*(out++) = '\n';
ret = out + osize - out_end;
leave:
return ret;
fail:
return -1;
}