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haproxy/src/http_htx.c
Christopher Faulet 7ff1ceaa5e MINOR: http_htx: Add functions to retrieve a specific occurrence of a header
There are 2 functions. The first one considers any comma as a delimiter for
distinct values. The second one considers full-line headers.
2018-11-18 22:08:55 +01:00

667 lines
19 KiB
C

/*
* Functions to manipulate HTTP messages using the internal representation.
*
* Copyright (C) 2018 HAProxy Technologies, Christopher Faulet <cfaulet@haproxy.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*
*/
#include <common/config.h>
#include <common/http.h>
#include <proto/http_htx.h>
#include <proto/htx.h>
/* Finds the start line in the HTX message stopping at the first
* end-of-message. It returns an empty start line when not found, otherwise, it
* returns the corresponding <struct h1_sl>.
*/
union h1_sl http_find_stline(const struct htx *htx)
{
union htx_sl *htx_sl;
union h1_sl sl;
int32_t pos;
for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
struct htx_blk *blk = htx_get_blk(htx, pos);
enum htx_blk_type type = htx_get_blk_type(blk);
if (type == HTX_BLK_REQ_SL) {
htx_sl = htx_get_blk_ptr(htx, blk);
sl.rq.meth = htx_sl->rq.meth;
sl.rq.m = ist2(htx_sl->rq.l, htx_sl->rq.m_len);
sl.rq.u = ist2(htx_sl->rq.l + htx_sl->rq.m_len, htx_sl->rq.u_len);
sl.rq.v = ist2(htx_sl->rq.l + htx_sl->rq.m_len + htx_sl->rq.u_len, htx_sl->rq.v_len);
return sl;
}
if (type == HTX_BLK_RES_SL) {
htx_sl = htx_get_blk_ptr(htx, blk);
sl.st.status = htx_sl->st.status;
sl.st.v = ist2(htx_sl->st.l, htx_sl->st.v_len);
sl.st.c = ist2(htx_sl->st.l + htx_sl->st.v_len, htx_sl->st.c_len);
sl.st.r = ist2(htx_sl->st.l + htx_sl->st.v_len + htx_sl->st.c_len, htx_sl->st.r_len);
return sl;
}
if (type == HTX_BLK_EOM)
break;
}
sl.rq.m = ist("");
sl.rq.u = ist("");
sl.rq.v = ist("");
return sl;
}
/* Finds the first or next occurrence of header <name> in the HTX message <htx>
* using the context <ctx>. This structure holds everything necessary to use the
* header and find next occurrence. If its <blk> member is NULL, the header is
* searched from the beginning. Otherwise, the next occurrence is returned. The
* function returns 1 when it finds a value, and 0 when there is no more. It is
* designed to work with headers defined as comma-separated lists. If <full> is
* set, it works on full-line headers in whose comma is not a delimiter but is
* part of the syntax. A special case, if ctx->value is NULL when searching for
* a new values of a header, the current header is rescanned. This allows
* rescanning after a header deletion.
*/
int http_find_header(const struct htx *htx, const struct ist name,
struct http_hdr_ctx *ctx, int full)
{
struct htx_blk *blk = ctx->blk;
struct ist n, v;
enum htx_blk_type type;
uint32_t pos;
if (blk) {
char *p;
pos = htx_get_blk_pos(htx, blk);
if (!ctx->value.ptr)
goto rescan_hdr;
if (full)
goto next_blk;
v = htx_get_blk_value(htx, blk);
p = ctx->value.ptr + ctx->value.len + ctx->lws_after;
v.len -= (p - v.ptr);
v.ptr = p;
if (!v.len)
goto next_blk;
/* Skip comma */
if (*(v.ptr) == ',') {
v.ptr++;
v.len--;
}
goto return_hdr;
}
if (!htx->used)
return 0;
pos = htx_get_head(htx);
while (1) {
rescan_hdr:
blk = htx_get_blk(htx, pos);
type = htx_get_blk_type(blk);
if (type != HTX_BLK_HDR)
goto next_blk;
if (name.len) {
/* If no name was passed, we want any header. So skip the comparison */
n = htx_get_blk_name(htx, blk);
if (!isteqi(n, name))
goto next_blk;
}
v = htx_get_blk_value(htx, blk);
return_hdr:
ctx->lws_before = 0;
ctx->lws_after = 0;
while (v.len && HTTP_IS_LWS(*v.ptr)) {
v.ptr++;
v.len--;
ctx->lws_before++;
}
if (!full)
v.len = http_find_hdr_value_end(v.ptr, v.ptr + v.len) - v.ptr;
while (v.len && HTTP_IS_LWS(*(v.ptr + v.len - 1))) {
v.len--;
ctx->lws_after++;
}
if (!v.len)
goto next_blk;
ctx->blk = blk;
ctx->value = v;
return 1;
next_blk:
if (pos == htx->tail)
break;
pos++;
if (pos >= htx->wrap)
pos = 0;
}
ctx->blk = NULL;
ctx->value = ist("");
ctx->lws_before = ctx->lws_after = 0;
return 0;
}
/* Adds a header block int the HTX message <htx>, just before the EOH block. It
* returns 1 on success, otherwise it returns 0.
*/
int http_add_header(struct htx *htx, const struct ist n, const struct ist v)
{
struct htx_blk *blk;
enum htx_blk_type type = htx_get_tail_type(htx);
int32_t prev;
blk = htx_add_header(htx, n, v);
if (!blk)
return 0;
if (unlikely(type < HTX_BLK_EOH))
return 1;
/* <blk> is the head, swap it iteratively with its predecessor to place
* it just before the end-of-header block. So blocks remains ordered. */
for (prev = htx_get_prev(htx, htx->tail); prev != -1; prev = htx_get_prev(htx, prev)) {
struct htx_blk *pblk = htx_get_blk(htx, prev);
enum htx_blk_type type = htx_get_blk_type(pblk);
/* Swap .addr and .info fields */
blk->addr ^= pblk->addr; pblk->addr ^= blk->addr; blk->addr ^= pblk->addr;
blk->info ^= pblk->info; pblk->info ^= blk->info; blk->info ^= pblk->info;
if (blk->addr == pblk->addr)
blk->addr += htx_get_blksz(pblk);
htx->front = prev;
/* Stop when end-of-header is reached */
if (type == HTX_BLK_EOH)
break;
blk = pblk;
}
return 1;
}
/* Replaces the request start line of the HTX message <htx> by <sl>. It returns
* 1 on success, otherwise it returns 0. The start line must be found in the
* message.
*/
int http_replace_reqline(struct htx *htx, const union h1_sl sl)
{
int32_t pos;
for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
struct htx_blk *blk = htx_get_blk(htx, pos);
enum htx_blk_type type = htx_get_blk_type(blk);
if (type == HTX_BLK_REQ_SL) {
blk = htx_replace_reqline(htx, blk, sl);
if (!blk)
return 0;
return 1;
}
if (type == HTX_BLK_EOM)
break;
}
return 0;
}
/* Replaces the response start line of the HTX message <htx> by <sl>. It returns
* 1 on success, otherwise it returns 0. The start line must be found in the
* message.
*/
int http_replace_resline(struct htx *htx, const union h1_sl sl)
{
int32_t pos;
for (pos = htx_get_head(htx); pos != -1; pos = htx_get_next(htx, pos)) {
struct htx_blk *blk = htx_get_blk(htx, pos);
enum htx_blk_type type = htx_get_blk_type(blk);
if (type == HTX_BLK_RES_SL) {
blk = htx_replace_resline(htx, blk, sl);
if (!blk)
return 0;
return 1;
}
if (type == HTX_BLK_EOM)
break;
}
return 0;
}
/* Replace the request method in the HTX message <htx> by <meth>. It returns 1
* on success, otherwise 0.
*/
int http_replace_req_meth(struct htx *htx, const struct ist meth)
{
struct buffer *temp = get_trash_chunk();
union h1_sl sl = http_find_stline(htx);
union h1_sl new_sl;
/* Start by copying old uri and version */
chunk_memcat(temp, sl.rq.u.ptr, sl.rq.u.len); /* uri */
chunk_memcat(temp, sl.rq.v.ptr, sl.rq.v.len); /* vsn */
/* create the new start line */
new_sl.rq.meth = find_http_meth(meth.ptr, meth.len);
new_sl.rq.m = meth;
new_sl.rq.u = ist2(temp->area, sl.rq.u.len);
new_sl.rq.v = ist2(temp->area + sl.rq.u.len, sl.rq.v.len);
return http_replace_reqline(htx, new_sl);
}
/* Replace the request uri in the HTX message <htx> by <uri>. It returns 1 on
* success, otherwise 0.
*/
int http_replace_req_uri(struct htx *htx, const struct ist uri)
{
struct buffer *temp = get_trash_chunk();
union h1_sl sl = http_find_stline(htx);
union h1_sl new_sl;
/* Start by copying old method and version */
chunk_memcat(temp, sl.rq.m.ptr, sl.rq.m.len); /* meth */
chunk_memcat(temp, sl.rq.v.ptr, sl.rq.v.len); /* vsn */
/* create the new start line */
new_sl.rq.meth = sl.rq.meth;
new_sl.rq.m = ist2(temp->area, sl.rq.m.len);
new_sl.rq.u = uri;
new_sl.rq.v = ist2(temp->area + sl.rq.m.len, sl.rq.v.len);
return http_replace_reqline(htx, new_sl);
}
/* Replace the request path in the HTX message <htx> by <path>. The host part
* and the query string are preserved. It returns 1 on success, otherwise 0.
*/
int http_replace_req_path(struct htx *htx, const struct ist path)
{
struct buffer *temp = get_trash_chunk();
union h1_sl sl = http_find_stline(htx);
union h1_sl new_sl;
struct ist p, uri;
size_t plen = 0;
p = http_get_path(sl.rq.u);
if (!p.ptr)
p = sl.rq.u;
while (plen < p.len && *(p.ptr + plen) != '?')
plen++;
/* Start by copying old method and version and create the new uri */
chunk_memcat(temp, sl.rq.m.ptr, sl.rq.m.len); /* meth */
chunk_memcat(temp, sl.rq.v.ptr, sl.rq.v.len); /* vsn */
chunk_memcat(temp, sl.rq.u.ptr, p.ptr - sl.rq.u.ptr); /* uri: host part */
chunk_memcat(temp, path.ptr, path.len); /* uri: new path */
chunk_memcat(temp, p.ptr + plen, p.len - plen); /* uri: QS part */
/* Get uri ptr and len */
uri.ptr = temp->area + sl.rq.m.len + sl.rq.v.len;
uri.len = sl.rq.u.len - plen + path.len;
/* create the new start line */
new_sl.rq.meth = sl.rq.meth;
new_sl.rq.m = ist2(temp->area, sl.rq.m.len);
new_sl.rq.u = uri;
new_sl.rq.v = ist2(temp->area + sl.rq.m.len, sl.rq.v.len);
return http_replace_reqline(htx, new_sl);
}
/* Replace the request query-string in the HTX message <htx> by <query>. The
* host part and the path are preserved. It returns 1 on success, otherwise
* 0.
*/
int http_replace_req_query(struct htx *htx, const struct ist query)
{
struct buffer *temp = get_trash_chunk();
union h1_sl sl = http_find_stline(htx);
union h1_sl new_sl;
struct ist q, uri;
int offset = 1;
q = sl.rq.u;
while (q.len > 0 && *(q.ptr) != '?') {
q.ptr++;
q.len--;
}
/* skip the question mark or indicate that we must insert it
* (but only if the format string is not empty then).
*/
if (q.len) {
q.ptr++;
q.len--;
}
else if (query.len > 1)
offset = 0;
/* Start by copying old method and version and create the new uri */
chunk_memcat(temp, sl.rq.m.ptr, sl.rq.m.len); /* meth */
chunk_memcat(temp, sl.rq.v.ptr, sl.rq.v.len); /* vsn */
chunk_memcat(temp, sl.rq.u.ptr, q.ptr - sl.rq.u.ptr); /* uri: host + path part */
chunk_memcat(temp, query.ptr + offset, query.len - offset); /* uri: new QS */
/* Get uri ptr and len */
uri.ptr = temp->area + sl.rq.m.len + sl.rq.v.len;
uri.len = sl.rq.u.len - q.len + query.len - offset;
/* create the new start line */
new_sl.rq.meth = sl.rq.meth;
new_sl.rq.m = ist2(temp->area, sl.rq.m.len);
new_sl.rq.u = uri;
new_sl.rq.v = ist2(temp->area + sl.rq.m.len, sl.rq.v.len);
return http_replace_reqline(htx, new_sl);
}
/* Replace the response status in the HTX message <htx> by <status>. It returns
* 1 on success, otherwise 0.
*/
int http_replace_res_status(struct htx *htx, const struct ist status)
{
struct buffer *temp = get_trash_chunk();
union h1_sl sl = http_find_stline(htx);
union h1_sl new_sl;
/* Start by copying old uri and version */
chunk_memcat(temp, sl.st.v.ptr, sl.st.v.len); /* vsn */
chunk_memcat(temp, sl.st.r.ptr, sl.st.r.len); /* reason */
/* create the new start line */
new_sl.st.status = strl2ui(status.ptr, status.len);
new_sl.st.v = ist2(temp->area, sl.st.v.len);
new_sl.st.c = status;
new_sl.st.r = ist2(temp->area + sl.st.v.len, sl.st.r.len);
return http_replace_resline(htx, new_sl);
}
/* Replace the response reason in the HTX message <htx> by <reason>. It returns
* 1 on success, otherwise 0.
*/
int http_replace_res_reason(struct htx *htx, const struct ist reason)
{
struct buffer *temp = get_trash_chunk();
union h1_sl sl = http_find_stline(htx);
union h1_sl new_sl;
/* Start by copying old uri and version */
chunk_memcat(temp, sl.st.v.ptr, sl.st.v.len); /* vsn */
chunk_memcat(temp, sl.st.c.ptr, sl.st.c.len); /* code */
/* create the new start line */
new_sl.st.status = sl.st.status;
new_sl.st.v = ist2(temp->area, sl.st.v.len);
new_sl.st.c = ist2(temp->area + sl.st.v.len, sl.st.c.len);
new_sl.st.r = reason;
return http_replace_resline(htx, new_sl);
}
/* Replaces a part of a header value referenced in the context <ctx> by
* <data>. It returns 1 on success, otherwise it returns 0. The context is
* updated if necessary.
*/
int http_replace_header_value(struct htx *htx, struct http_hdr_ctx *ctx, const struct ist data)
{
struct htx_blk *blk = ctx->blk;
char *start;
struct ist v;
uint32_t len, off;
if (!blk)
return 0;
v = htx_get_blk_value(htx, blk);
start = ctx->value.ptr - ctx->lws_before;
len = ctx->lws_before + ctx->value.len + ctx->lws_after;
off = start - v.ptr;
blk = htx_replace_blk_value(htx, blk, ist2(start, len), data);
if (!blk)
return 0;
v = htx_get_blk_value(htx, blk);
ctx->blk = blk;
ctx->value.ptr = v.ptr + off;
ctx->value.len = data.len;
ctx->lws_before = ctx->lws_after = 0;
return 1;
}
/* Fully replaces a header referenced in the context <ctx> by the name <name>
* with the value <value>. It returns 1 on success, otherwise it returns 0. The
* context is updated if necessary.
*/
int http_replace_header(struct htx *htx, struct http_hdr_ctx *ctx,
const struct ist name, const struct ist value)
{
struct htx_blk *blk = ctx->blk;
if (!blk)
return 0;
blk = htx_replace_header(htx, blk, name, value);
if (!blk)
return 0;
ctx->blk = blk;
ctx->value = ist(NULL);
ctx->lws_before = ctx->lws_after = 0;
return 1;
}
/* Remove one value of a header. This only works on a <ctx> returned by
* http_find_header function. The value is removed, as well as surrounding commas
* if any. If the removed value was alone, the whole header is removed. The
* <ctx> is always updated accordingly, as well as the HTX message <htx>. It
* returns 1 on success. Otherwise, it returns 0. The <ctx> is always left in a
* form that can be handled by http_find_header() to find next occurrence.
*/
int http_remove_header(struct htx *htx, struct http_hdr_ctx *ctx)
{
struct htx_blk *blk = ctx->blk;
char *start;
struct ist v;
uint32_t len;
if (!blk)
return 0;
start = ctx->value.ptr - ctx->lws_before;
len = ctx->lws_before + ctx->value.len + ctx->lws_after;
v = htx_get_blk_value(htx, blk);
if (len == v.len) {
blk = htx_remove_blk(htx, blk);
if (blk || !htx->used) {
ctx->blk = blk;
ctx->value = ist2(NULL, 0);
ctx->lws_before = ctx->lws_after = 0;
}
else {
ctx->blk = htx_get_blk(htx, htx->tail);
ctx->value = htx_get_blk_value(htx, ctx->blk);
ctx->lws_before = ctx->lws_after = 0;
}
return 1;
}
/* This was not the only value of this header. We have to remove the
* part pointed by ctx->value. If it is the last entry of the list, we
* remove the last separator.
*/
if (start == v.ptr) {
/* It's the first header part but not the only one. So remove
* the comma after it. */
len++;
}
else {
/* There is at least one header part before the removed one. So
* remove the comma between them. */
start--;
len++;
}
/* Update the block content and its len */
memmove(start, start+len, v.len-len);
htx_set_blk_value_len(blk, v.len-len);
/* Update HTX msg */
htx->data -= len;
/* Finally update the ctx */
ctx->value.ptr = start;
ctx->value.len = 0;
ctx->lws_before = ctx->lws_after = 0;
return 1;
}
/* Return in <vptr> and <vlen> the pointer and length of occurrence <occ> of
* header whose name is <hname> of length <hlen>. If <ctx> is null, lookup is
* performed over the whole headers. Otherwise it must contain a valid header
* context, initialised with ctx->blk=NULL for the first lookup in a series. If
* <occ> is positive or null, occurrence #occ from the beginning (or last ctx)
* is returned. Occ #0 and #1 are equivalent. If <occ> is negative (and no less
* than -MAX_HDR_HISTORY), the occurrence is counted from the last one which is
* -1. The value fetch stops at commas, so this function is suited for use with
* list headers.
* The return value is 0 if nothing was found, or non-zero otherwise.
*/
unsigned int http_get_htx_hdr(const struct htx *htx, const struct ist hdr,
int occ, struct http_hdr_ctx *ctx, char **vptr, size_t *vlen)
{
struct http_hdr_ctx local_ctx;
struct ist val_hist[MAX_HDR_HISTORY];
unsigned int hist_idx;
int found;
if (!ctx) {
local_ctx.blk = NULL;
ctx = &local_ctx;
}
if (occ >= 0) {
/* search from the beginning */
while (http_find_header(htx, hdr, ctx, 0)) {
occ--;
if (occ <= 0) {
*vptr = ctx->value.ptr;
*vlen = ctx->value.len;
return 1;
}
}
return 0;
}
/* negative occurrence, we scan all the list then walk back */
if (-occ > MAX_HDR_HISTORY)
return 0;
found = hist_idx = 0;
while (http_find_header(htx, hdr, ctx, 0)) {
val_hist[hist_idx] = ctx->value;
if (++hist_idx >= MAX_HDR_HISTORY)
hist_idx = 0;
found++;
}
if (-occ > found)
return 0;
/* OK now we have the last occurrence in [hist_idx-1], and we need to
* find occurrence -occ. 0 <= hist_idx < MAX_HDR_HISTORY, and we have
* -10 <= occ <= -1. So we have to check [hist_idx%MAX_HDR_HISTORY+occ]
* to remain in the 0..9 range.
*/
hist_idx += occ + MAX_HDR_HISTORY;
if (hist_idx >= MAX_HDR_HISTORY)
hist_idx -= MAX_HDR_HISTORY;
*vptr = val_hist[hist_idx].ptr;
*vlen = val_hist[hist_idx].len;
return 1;
}
/* Return in <vptr> and <vlen> the pointer and length of occurrence <occ> of
* header whose name is <hname> of length <hlen>. If <ctx> is null, lookup is
* performed over the whole headers. Otherwise it must contain a valid header
* context, initialised with ctx->blk=NULL for the first lookup in a series. If
* <occ> is positive or null, occurrence #occ from the beginning (or last ctx)
* is returned. Occ #0 and #1 are equivalent. If <occ> is negative (and no less
* than -MAX_HDR_HISTORY), the occurrence is counted from the last one which is
* -1. This function differs from http_get_hdr() in that it only returns full
* line header values and does not stop at commas.
* The return value is 0 if nothing was found, or non-zero otherwise.
*/
unsigned int http_get_htx_fhdr(const struct htx *htx, const struct ist hdr,
int occ, struct http_hdr_ctx *ctx, char **vptr, size_t *vlen)
{
struct http_hdr_ctx local_ctx;
struct ist val_hist[MAX_HDR_HISTORY];
unsigned int hist_idx;
int found;
if (!ctx) {
local_ctx.blk = NULL;
ctx = &local_ctx;
}
if (occ >= 0) {
/* search from the beginning */
while (http_find_header(htx, hdr, ctx, 1)) {
occ--;
if (occ <= 0) {
*vptr = ctx->value.ptr;
*vlen = ctx->value.len;
return 1;
}
}
return 0;
}
/* negative occurrence, we scan all the list then walk back */
if (-occ > MAX_HDR_HISTORY)
return 0;
found = hist_idx = 0;
while (http_find_header(htx, hdr, ctx, 1)) {
val_hist[hist_idx] = ctx->value;
if (++hist_idx >= MAX_HDR_HISTORY)
hist_idx = 0;
found++;
}
if (-occ > found)
return 0;
/* OK now we have the last occurrence in [hist_idx-1], and we need to
* find occurrence -occ. 0 <= hist_idx < MAX_HDR_HISTORY, and we have
* -10 <= occ <= -1. So we have to check [hist_idx%MAX_HDR_HISTORY+occ]
* to remain in the 0..9 range.
*/
hist_idx += occ + MAX_HDR_HISTORY;
if (hist_idx >= MAX_HDR_HISTORY)
hist_idx -= MAX_HDR_HISTORY;
*vptr = val_hist[hist_idx].ptr;
*vlen = val_hist[hist_idx].len;
return 1;
}