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Refactoring

This commit is contained in:
dave 2018-05-25 17:12:09 -07:00
parent bb211f20e2
commit c1d99a1f86
6 changed files with 186 additions and 157 deletions
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2
src/Makefile
View File

@ -2,7 +2,7 @@ CC=gcc -Wall
CFLAGS=-g -I.
CFLAGS_STATIC=$(CCLAGS) --static
DEPS=
OBJ=main.o pfparser.o
OBJ=main.o pfparser.o sysparser.o
%.o: %.c $(DEPS)
$(CC) -c -o $@ $< $(CFLAGS)

177
src/main.c
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@ -11,165 +11,25 @@
#include <netdb.h>
#include <limits.h>
#include "helpers.h"
#include "pfparser.h"
// #include "pfparser.h"
#include "sysparser.h"
#include <signal.h>
/*UDP server-related mostly lifted from https://cs.nyu.edu/~mwalfish/classes/16sp/classnotes/handout01.pdf*/
#define DF_MONTH_LEN 9
/*TODO numeric indicator for month?*/
struct Datefields {
char month[DF_MONTH_LEN];
int day;
int hour;
int minute;
int second;
};
/*TODO check max app name length*/
#define MSG_APP_LEN 64
struct Message {
int priority;
char application[MSG_APP_LEN];
struct Datefields date;
pf_message data;
};
void panic(const char* s) {
perror(s);
exit(1);
}
int parse_priority(char* message, int* priority, int* position) {
/*
Given a string that begins with a message something like: <123>foo
Parse out the number (123) and place it in the passed `priority` int pointer
The position after the final `>` will be placed in the passed `position` int pointer
Returns 0 on success or something else on failure
*/
/*Must have >3 chars to form <x> priority*/
if (strlen(message) < 3) return 1;
/*Must start with <*/
if (message[0] != '<') return 1;
char digits[4];
memset(&digits, '\0', sizeof(digits));
int num_digits = 0;
int pos = 1;
/*bool found_priority_end = false; // TODO*/
while (pos < 4) {
if(!isdigit(message[pos])) return 1; /*priority must be numeric*/
digits[num_digits] = message[pos];
num_digits++;
pos++;
if (message[pos] == '>') {
break;
}
}
/*TODO if escape the loop because pos >= 4, we never found '>'*/
if (num_digits == 0) return 1; /*empty priority <> ?*/
*priority = atoi(digits);
*position = pos;
return 0;
}
int parse_datefield(char* message, struct Datefields* date, int* position) {
/*
Given a message+position pointers, where message + position in a string like:
May 10 03:09:59 filterlog: 5,,,....
Parse out the date and place the fields in the passed datefields struct pointer
Position will be advanced to the character after the parsed data
*/
/*char month[8];
memset(&month, '\0', sizeof(month)); makes valgrind happy as the above char contains uninitialized memory*/
int date_length;
if(sscanf(message + *position, "%"STR(DF_MONTH_LEN)"s %d %d:%d:%d%n",
date->month, &(date->day), &(date->hour), &(date->minute), &(date->second), &date_length) != 5) {
return 1; /*Failed to parse all desired fields*/
}
*position += date_length;
return 0;
}
int parse_application(char* message, char* application, int* position) {
int app_length;
if(sscanf(message + *position, "%"STR(MSG_APP_LEN)"s%n", application, &app_length) != 1) { /*%n not counted in returned field count*/
return 1; /*Failed to parse all desired fields*/
}
if(strlen(application) < 2) return 1; /*Expect at least chars*/
application[app_length-1] = '\0'; /*Remove the trailing :*/
*position += app_length;
return 0;
}
int parse_message(struct Message* result, char* message) {
/*
parse a message like:
<134>May 10 03:09:59 filterlog: 5,,,1000000103,cpsw0,match,block,in,4,0x20,,239,27547,0,none,6,tcp,40,185.216.140.37,24.4.129.164,57159,11111,0,S,3919167832,,1024,,
Format:
<priority>VERSION ISOTIMESTAMP HOSTNAME APPLICATION PID MESSAGEID STRUCTURED-DATA MSG
Assumes null termed string
*/
int priority = 0;
int position = 0;
if(parse_priority(message, &priority, &position) != 0) return 1;
result->priority = priority;
position++; /*Now sits on the first character of the ISOTIMESTAMP*/
/*Parse ISOTIMESTAMP
Note: does not parse a full iso timestamp, only the format above*/
struct Datefields date;
if(parse_datefield(message, &date, &position) != 0) {
return 1;
}
result->date = date;
position++; /*position now at beginning of HOSTNAME field*/
/*Parse APPLICATION
filterlog: 5,,,1000000103,cpsw0,match....*/
char application[MSG_APP_LEN];
if(parse_application(message, application, &position) != 0) return 1;
memcpy(result->application, application, sizeof(application));
position += 1; /*pass over the space*/
/*printf("remaining: '%s'\n", message + position);*/
/*trim original message to only the CSV portion*/
int msglen = strlen(message);
int datalen = msglen - position;
memmove(message, &message[position], datalen);
/*zero the rest of the message*/
memset(&message[datalen], 0, msglen - datalen);
/*pf_message result_msg;*/
if(pfparse_message(message, &(result->data)) != 0) return 1;
/*char msg_remaining[4096];
memset(&msg_remaining, '\0', sizeof(msg_remaining));
memcpy(msg_remaining, &message[position], strlen(message) - position);
printf("'%s'\n", msg_remaining);
or
memmove(message, &message[position], strlen(message) - position);
printf("'%s'\n", message);*/
return 0;
}
int running = 1;
int sock_fd;
void handler(int signum) {
printf("Exiting on signal %s\n", strsignal(signum));
void sig_handler(int signum) {
printf("\nExiting on signal %s\n", strsignal(signum));
running = 0; /* shut down the loop */
shutdown(sock_fd, SHUT_RDWR); /* break the listener socket */
close(sock_fd);
@ -182,8 +42,8 @@ int main(int argc, char** argv) {
exit(1);
}
signal(SIGTERM, handler);
signal(SIGINT, handler);
signal(SIGTERM, sig_handler);
signal(SIGINT, sig_handler);
/*Parse port number to integer*/
char* portend;
@ -232,16 +92,29 @@ int main(int argc, char** argv) {
/*TODO should we check that msg[size_recvd] == \0 ?
printf("From host %s src port %d got message %.*s\n",
inet_ntoa(my_peer_addr.sin_addr), ntohs(my_peer_addr.sin_port), size_recvd, msg);*/
struct Message result;
struct SysMessage result;
memset(&result, 0, sizeof(result)); /* Doing this or setting result above to `= {};` seems to make valgrind happy */
/*printf("\nsize: %lu\n\n", sizeof(result)); // curious how big the struct gets
// printf("msg[size_recvd] is: %d", msg[size_recvd]);*/
msg[size_recvd] = '\0'; /*We receive 1 full string at a time*/
if(parse_message(&result, msg) != 1) {
printf("message is valid:\n\tpriority: %d\n\tapplication: %s\n\tDate: %s %d %02d:%02d:%02d\n"
"\tInterface: %s\n\tIP version: %d\n",
result.priority, result.application, result.date.month, result.date.day, result.date.hour,
result.date.minute, result.date.second, result.data.iface, result.data.ipversion);
if(sysmsg_parse(&result, msg) != 0) {
printf("Failed to parse message: %s", msg);
} else {
printf("syslogmessage is valid:\n\tpriority: %d\n\tapplication: %s\n\tDate: %s %d %02d:%02d:%02d\n\t\n",
result.priority, result.application, result.date.month, result.date.day, result.date.hour,
result.date.minute, result.date.second);
pf_data fwdata;
memset(&fwdata, 0, sizeof(fwdata));
if(pfparse_message(msg, &fwdata) != 0) {
printf("Failed to parse pfsense data: %s", msg);
} else {
printf("IP Data:\n\tInterface: %s\n\tIP version: %d\n",
fwdata.iface, fwdata.ipversion);
}
}
}

2
src/pfparser.c
View File

@ -5,7 +5,7 @@
int pfparse_message(char* message, pf_message* result) {
int pfparse_message(char* message, pf_data* result) {
printf("pfparse: '%s'\n", message);
char* token;

6
src/pfparser.h
View File

@ -17,15 +17,15 @@ typedef enum pf_direction {
pf_dir_out
} pf_direction;
typedef struct pf_message {
typedef struct pf_data {
int rulenum;
char iface[IFACE_LEN];
pf_hit_reason reason;
pf_hit_action action;
pf_direction direction;
int ipversion;
} pf_message;
} pf_data;
int pfparse_message(char* message, pf_message* result);
int pfparse_message(char* message, pf_data* result);

130
src/sysparser.c Normal file
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@ -0,0 +1,130 @@
#include "sysparser.h"
#include <stdio.h>
#include "helpers.h"
#include <string.h>
#include <ctype.h>
#include <stdlib.h>
int parse_priority(char* message, int* priority, int* position) {
/*
Given a string that begins with a message something like: <123>foo
Parse out the number (123) and place it in the passed `priority` int pointer
The position after the final `>` will be placed in the passed `position` int pointer
Returns 0 on success or something else on failure
*/
/*Must have >3 chars to form <x> priority*/
if (strlen(message) < 3) return 1;
/*Must start with <*/
if (message[0] != '<') return 1;
char digits[4];
memset(&digits, '\0', sizeof(digits));
int num_digits = 0;
int pos = 1;
/*bool found_priority_end = false; // TODO*/
while (pos < 4) {
if(!isdigit(message[pos])) return 1; /*priority must be numeric*/
digits[num_digits] = message[pos];
num_digits++;
pos++;
if (message[pos] == '>') {
break;
}
}
/*TODO if escape the loop because pos >= 4, we never found '>'*/
if (num_digits == 0) return 1; /*empty priority <> ?*/
*priority = atoi(digits);
*position = pos;
return 0;
}
int parse_datefield(char* message, struct Datefields* date, int* position) {
/*
Given a message+position pointers, where message + position in a string like:
May 10 03:09:59 filterlog: 5,,,....
Parse out the date and place the fields in the passed datefields struct pointer
Position will be advanced to the character after the parsed data
*/
/*char month[8];
memset(&month, '\0', sizeof(month)); makes valgrind happy as the above char contains uninitialized memory*/
int date_length;
if(sscanf(message + *position, "%"STR(DF_MONTH_LEN)"s %d %d:%d:%d%n",
date->month, &(date->day), &(date->hour), &(date->minute), &(date->second), &date_length) != 5) {
return 1; /*Failed to parse all desired fields*/
}
*position += date_length;
return 0;
}
int parse_application(char* message, char* application, int* position) {
int app_length;
if(sscanf(message + *position, "%"STR(MSG_APP_LEN)"s%n", application, &app_length) != 1) { /*%n not counted in returned field count*/
return 1; /*Failed to parse all desired fields*/
}
if(strlen(application) < 2) return 1; /*Expect at least chars*/
application[app_length-1] = '\0'; /*Remove the trailing :*/
*position += app_length;
return 0;
}
int sysmsg_parse(struct SysMessage* result, char* message) {
/*
parse a message like:
<134>May 10 03:09:59 filterlog: 5,,,1000000103,cpsw0,match,block,in,4,0x20,,239,27547,0,none,6,tcp,40,185.216.140.37,24.4.129.164,57159,11111,0,S,3919167832,,1024,,
Format:
<priority>VERSION ISOTIMESTAMP HOSTNAME APPLICATION PID MESSAGEID STRUCTURED-DATA MSG
Assumes null termed string
Param message will be transformed to the MSG field
*/
int priority = 0;
int position = 0;
if(parse_priority(message, &priority, &position) != 0) return 1;
result->priority = priority;
position++; /*Now sits on the first character of the ISOTIMESTAMP*/
/*Parse ISOTIMESTAMP
Note: does not parse a full iso timestamp, only the format above*/
struct Datefields date;
if(parse_datefield(message, &date, &position) != 0) {
return 1;
}
result->date = date;
position++; /*position now at beginning of HOSTNAME field*/
/*Parse APPLICATION
filterlog: 5,,,1000000103,cpsw0,match....*/
char application[MSG_APP_LEN];
if(parse_application(message, application, &position) != 0) return 1;
memcpy(result->application, application, sizeof(application));
position += 1; /*pass over the space*/
/*printf("remaining: '%s'\n", message + position);*/
/*trim original message to only the CSV portion*/
int msglen = strlen(message);
int datalen = msglen - position;
memmove(message, &message[position], datalen);
/*zero the rest of the message*/
memset(&message[datalen], 0, msglen - datalen);
/*pf_message result_msg;*/
// if(pfparse_message(message, &(result->data)) != 0) return 1;
/* put message in result */
// memcpy(&(result->message), message, strlen(message));
// result->message = message + position;
/*char msg_remaining[4096];
memset(&msg_remaining, '\0', sizeof(msg_remaining));
memcpy(msg_remaining, &message[position], strlen(message) - position);
printf("'%s'\n", msg_remaining);
or
memmove(message, &message[position], strlen(message) - position);
printf("'%s'\n", message);*/
return 0;
}

26
src/sysparser.h Normal file
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@ -0,0 +1,26 @@
#include "pfparser.h"
#define DF_MONTH_LEN 9
/*TODO numeric indicator for month?*/
struct Datefields {
char month[DF_MONTH_LEN];
int day;
int hour;
int minute;
int second;
};
/*TODO check max app name length*/
#define MSG_APP_LEN 64
struct SysMessage {
int priority;
char application[MSG_APP_LEN];
struct Datefields date;
// char message;
// pf_message data;
};
int sysmsg_parse(struct SysMessage* result, char* message);