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/* ISC license. */
#include <sys/types.h>
#include <string.h>
#include <stdint.h>
#include <skalibs/uint64.h>
#include <skalibs/types.h>
#include <skalibs/fmtscan.h>
#include <skalibs/buffer.h>
#include <skalibs/stralloc.h>
#include <skalibs/djbunix.h>
#include <skalibs/ip46.h>
#include <skalibs/skamisc.h>
#include "mgetuid.h"
#ifdef DEBUG
#include <skalibs/strerr2.h>
#define bug(a) do { strerr_warn4x("bug parsing ", a, "remaining: ", cur) ; return 0 ; } while (0)
#else
#define bug(a) return 0
#endif
#define LINESIZE 256
static int skipspace (char **s)
{
while (**s && ((**s == ' ') || (**s == '\t')))
(*s)++ ;
return (int)**s ;
}
static void reverse_address (char *s, size_t n)
{
size_t i = n >> 1 ;
while (i--)
{
char tmp = s[i] ;
s[i] = s[n-1-i] ;
s[n-1-i] = tmp ;
}
}
static int parseline (char *s, size_t len, uid_t *u, char *la, uint16_t *lp, char *ra, uint16_t *rp, int is6)
{
char *cur = s ;
size_t pos ;
uint64_t uu ;
uint32_t junk ;
unsigned int iplen = is6 ? 16 : 4 ;
if (!skipspace(&cur)) bug("initial whitespace") ;
pos = uint32_scan(cur, &junk) ; /* sl */
if (!pos || (cur-s+1+pos) > len) bug("sl") ;
cur += pos ;
if ((*cur++) != ':') bug("sl:") ;
if (!skipspace(&cur)) bug("sl: SPACE") ;
if ((cur - s + 1 + iplen) > len) bug("local_address") ;
pos = ucharn_scan(cur, la, iplen) ; /* local_address */
reverse_address(la, iplen) ;
if (!pos) bug("local_address") ;
cur += pos ;
if ((*cur++) != ':') bug("local_address:") ;
pos = uint16_xscan(cur, lp) ; /* :port */
if (!pos || (cur-s+pos) > len) bug("local_port") ;
cur += pos ;
if (!skipspace(&cur)) bug("local_port SPACE") ;
if ((cur - s + 1 + iplen) > len) bug("remote_address") ;
pos = ucharn_scan(cur, ra, iplen) ; /* remote_address */
reverse_address(ra, iplen) ;
if (!pos) bug("remote_address") ;
cur += pos ;
if ((*cur++) != ':') bug("remote_address:") ;
pos = uint16_xscan(cur, rp) ; /* :port */
if (!pos || (cur-s+pos) > len) bug("remote_port") ;
cur += pos ;
if (!skipspace(&cur)) bug("remote_port SPACE");
pos = uint32_xscan(cur, &junk) ; /* st */
if (!pos || (cur-s+pos) > len) bug("st") ;
cur += pos ;
if (!skipspace(&cur)) bug("st SPACE") ;
pos = uint32_xscan(cur, &junk) ; /* tx_queue */
if (!pos || (cur-s+1+pos) > len) bug("tx_queue") ;
cur += pos ;
if ((*cur++) != ':') bug("tx_queue:") ;
pos = uint32_xscan(cur, &junk) ; /* rx_queue */
if (!pos || (cur-s+pos) > len) bug("rx_queue") ;
cur += pos ;
if (!skipspace(&cur)) bug("rx_queue SPACE") ;
pos = uint32_xscan(cur, &junk) ; /* tr */
if (!pos || (cur-s+1+pos) > len) bug("tr") ;
cur += pos ;
if ((*cur++) != ':') bug("tr:") ;
pos = uint32_xscan(cur, &junk) ; /* tm->when */
if (!pos || (cur-s+pos) > len) bug("tm->when") ;
cur += pos ;
if (!skipspace(&cur)) bug("tm->when SPACE") ;
pos = uint32_xscan(cur, &junk) ; /* retrnsmt */
if (!pos || (cur-s+pos) > len) bug("retrnsmt") ;
cur += pos ;
if (!skipspace(&cur)) bug("retrnsmt SPACE") ;
pos = uint64_scan(cur, &uu) ; /* uid */
if (!pos || (cur-s+1+pos) > len) bug("uid") ;
*u = uu ;
return 1 ;
}
#ifdef DEBUG
static void debuglog (uint16_t a, uint16_t b, unsigned int c, char const *d, char const *e, int is6)
{
char sa[UINT16_FMT] ;
char sb[UINT16_FMT] ;
char sc[UINT_FMT] ;
char sd[IP46_FMT] ;
char se[IP46_FMT] ;
sa[uint16_fmt(sa, a)] = 0 ;
sb[uint16_fmt(sb, b)] = 0 ;
sc[uint_fmt(sc, c)] = 0 ;
sd[is6 ? ip6_fmt(sd, d) : ip4_fmt(sd, d)] = 0 ;
se[is6 ? ip6_fmt(se, e) : ip4_fmt(se, e)] = 0 ;
buffer_puts(buffer_2, sd) ;
buffer_puts(buffer_2, ":") ;
buffer_puts(buffer_2, sa) ;
buffer_puts(buffer_2, " , ") ;
buffer_puts(buffer_2, se) ;
buffer_puts(buffer_2, ":") ;
buffer_puts(buffer_2, sb) ;
buffer_puts(buffer_2, " -> ") ;
buffer_puts(buffer_2, sc) ;
buffer_putsflush(buffer_2, "\n") ;
}
#endif
uid_t mgetuid (ip46_t const *localaddr, uint16_t localport, ip46_t const *remoteaddr, uint16_t remoteport)
{
int r ;
uid_t u = -2 ;
stralloc line = STRALLOC_ZERO ;
buffer b ;
char y[BUFFER_INSIZE] ;
int is6 = ip46_is6(localaddr) ;
int fd = open_readb(is6 ? "/proc/net/tcp6" : "/proc/net/tcp") ;
if (fd == -1) return -2 ;
buffer_init(&b, &buffer_read, fd, y, BUFFER_INSIZE_SMALL) ;
if (skagetln(&b, &line, '\n') < 1) goto err ;
#ifdef DEBUG
line.s[line.len-1] = 0 ;
debuglog(localport, remoteport, 65535, localaddr->ip, remoteaddr->ip, is6) ;
#endif
for (;;)
{
char la[16] ;
char ra[16] ;
uid_t nu ;
uint16_t lp, rp ;
line.len = 0 ;
r = skagetln(&b, &line, '\n') ;
if (r <= 0) { u = -1 ; break ; }
line.s[line.len-1] = 0 ;
if (!parseline(line.s, line.len, &nu, la, &lp, ra, &rp, is6)) break ;
#ifdef DEBUG
debuglog(lp, rp, nu, la, ra, is6) ;
#endif
if ((lp == localport) && (rp == remoteport)
&& !memcmp(la, localaddr->ip, is6 ? 16 : 4)
&& !memcmp(ra, remoteaddr->ip, is6 ? 16 : 4))
{
u = nu ; break ;
}
}
stralloc_free(&line) ;
err:
fd_close(fd) ;
return u ;
}
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