Introduce and use nd_trunc(). [skip ci]

This new function is a part of item 2 of the longjmp() conversion plan
Francois-Xavier proposed on tcpdump-workers. As a noreturn function, it
can fit uniformly at the end of any decoder function, regardless if void
or not, for example:

const u_char *
something_print (netdissect_options *ndo, const u_char *cp, u_int len)
{
  /* (some normal decoding) */
  ND_TCHECK_2(cp);
  /* (some more normal decoding) */
  return cp + len;

trunc:
  nd_trunc(ndo);
  /* The compiler does not warn about a missing return. */
}

1 files changed, 6 insertions, 6 deletions

diff --git a/addrtoname.h b/addrtoname.h
index 8a262aa7..b50739f3 100644
--- a/addrtoname.h
+++ b/addrtoname.h
@@ -68,7 +68,7 @@ get_linkaddr_string(netdissect_options *ndo, const uint8_t *p,
     const unsigned int type, const unsigned int len)
 {
         if (!ND_TTEST_LEN(p, len))
-                longjmp(ndo->ndo_truncated, 1);
+                nd_trunc(ndo);
         return linkaddr_string(ndo, p, type, len);
 }
 
@@ -76,7 +76,7 @@ static inline const char *
 get_etheraddr_string(netdissect_options *ndo, const uint8_t *p)
 {
         if (!ND_TTEST_LEN(p, MAC_ADDR_LEN))
-                longjmp(ndo->ndo_truncated, 1);
+                nd_trunc(ndo);
         return etheraddr_string(ndo, p);
 }
 
@@ -84,7 +84,7 @@ static inline const char *
 get_le64addr_string(netdissect_options *ndo, const u_char *p)
 {
         if (!ND_TTEST_8(p))
-                longjmp(ndo->ndo_truncated, 1);
+                nd_trunc(ndo);
         return le64addr_string(ndo, p);
 }
 
@@ -93,7 +93,7 @@ get_isonsap_string(netdissect_options *ndo, const uint8_t *nsap,
     u_int nsap_length)
 {
 	if (!ND_TTEST_LEN(nsap, nsap_length))
-                longjmp(ndo->ndo_truncated, 1);
+                nd_trunc(ndo);
         return isonsap_string(ndo, nsap, nsap_length);
 }
 
@@ -101,7 +101,7 @@ static inline const char *
 get_ipaddr_string(netdissect_options *ndo, const u_char *p)
 {
         if (!ND_TTEST_4(p))
-                longjmp(ndo->ndo_truncated, 1);
+                nd_trunc(ndo);
         return ipaddr_string(ndo, p);
 }
 
@@ -109,7 +109,7 @@ static inline const char *
 get_ip6addr_string(netdissect_options *ndo, const u_char *p)
 {
         if (!ND_TTEST_16(p))
-                longjmp(ndo->ndo_truncated, 1);
+                nd_trunc(ndo);
         return ip6addr_string(ndo, p);
 }