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/* http_parser.c
*
* This file contains functions to parse HTTP headers.
*
* File begun on 2018-11-13
*
* Created by:
* - Théo Bertin (theo.bertin@advens.fr)
*
* With:
* - François Bernard (francois.bernard@isen.yncrea.fr)
* - Tianyu Geng (tianyu.geng@isen.yncrea.fr)
*
* This file is part of rsyslog.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
* -or-
* see COPYING.ASL20 in the source distribution
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "config.h"
#include "parsers.h"
static const char *keywords[] = {
"OPTIONS",
"GET",
"HEAD",
"POST",
"PUT",
"DELETE",
"TRACE",
"CONNECT",
"HTTP",
NULL
};
static inline char *string_split(char **initString, const char *delimiterString) {
char *ret = *initString;
if (*initString) {
char *pos = strstr(*initString, delimiterString);
if (pos) {
*initString = pos;
**initString = '\0';
*initString += strlen(delimiterString);
} else {
*initString = NULL;
}
}
return ret;
}
static inline int has_status_keyword(char *http) {
const char *found;
int i;
for (i = 0; keywords[i] != NULL; i++) {
found = strstr(http, keywords[i]);
if (found && (found - http) < 20) {
return 1;
}
}
return 0;
}
/*
* This function catches HTTP header fields and status line
* and adds them to the provided json object
*/
static inline void catch_status_and_fields(char *header, struct json_object *jparent) {
DBGPRINTF("catch_status_and_fields\n");
struct json_object *fields = json_object_new_object();
char *statusLine = string_split(&header, "\r\n");
char *firstPart, *secondPart, *thirdPart;
firstPart = string_split(&statusLine, " ");
secondPart = string_split(&statusLine, " ");
thirdPart = statusLine;
if (firstPart && secondPart && thirdPart) {
if (strstr(firstPart, "HTTP")) {
json_object_object_add(jparent, "HTTP_version", json_object_new_string(firstPart));
json_object_object_add(jparent, "HTTP_status_code", json_object_new_string(secondPart));
json_object_object_add(jparent, "HTTP_reason", json_object_new_string(thirdPart));
} else {
json_object_object_add(jparent, "HTTP_method", json_object_new_string(firstPart));
json_object_object_add(jparent, "HTTP_request_URI", json_object_new_string(secondPart));
json_object_object_add(jparent, "HTTP_version", json_object_new_string(thirdPart));
}
}
char *fieldValue = string_split(&header, "\r\n");
char *field, *value;
while (fieldValue) {
field = string_split(&fieldValue, ":");
value = fieldValue;
if (value) {
while (*value == ' ') { value++; }
DBGPRINTF("got header field -> '%s': '%s'\n", field, value);
json_object_object_add(fields, field, json_object_new_string(value));
}
fieldValue = string_split(&header, "\r\n");
}
json_object_object_add(jparent, "HTTP_header_fields", fields);
return;
}
/*
* This function parses the bytes in the received packet to extract HTTP metadata.
*
* its parameters are:
* - a pointer on the list of bytes representing the packet
* the beginning of the header will be checked by the function
* - the size of the list passed as first parameter
* - a pointer on a json_object, containing all the metadata recovered so far
* this is also where HTTP metadata will be added
*
* This function returns a structure containing the data unprocessed by this parser
* or the ones after (as a list of bytes), and the length of this data.
*/
data_ret_t *http_parse(const uchar *packet, int pktSize, struct json_object *jparent) {
DBGPRINTF("http_parse\n");
DBGPRINTF("packet size %d\n", pktSize);
if (pktSize < 6) {
RETURN_DATA_AFTER(0)
}
char *pHttp = malloc(pktSize + 1);
char *http = pHttp;
memcpy(http, packet, pktSize);
*(http + pktSize) = '\0';
if (!has_status_keyword(http)) {
free(pHttp);
RETURN_DATA_AFTER(0)
}
char *header = string_split(&http, "\r\n\r\n");
catch_status_and_fields(header, jparent);
free(pHttp);
RETURN_DATA_AFTER(0)
}
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