res_pjproject: Fix DTLS client check failing on some platforms

Certain platforms (mainly BSD derivatives) have an additional length
field in `sockaddr_in6` and `sockaddr_in`.
`ast_sockaddr_from_pj_sockaddr()` does not take this field into account
when copying over values from the `pj_sockaddr` into the `ast_sockaddr`.
The resulting `ast_sockaddr` will have an uninitialized value for
`sin6_len`/`sin_len` while the other `ast_sockaddr` (not converted from
a `pj_sockaddr`) to check against in `ast_sockaddr_pj_sockaddr_cmp()`
has the correct length value set.

This has the effect that `ast_sockaddr_cmp()` will always indicate
an address mismatch, because it does a bitwise comparison, and all DTLS
packets are dropped even if addresses and ports match.

`ast_sockaddr_from_pj_sockaddr()` now checks whether the length fields
are available on the current platform and sets the values accordingly.

Resolves: #505
(cherry picked from commit c251afadb9)

configure

@@ -28233,6 +28233,25 @@ printf "%s\n" "#define HAVE_STRUCT_STAT_ST_MTIMESPEC 1" >>confdefs.h
 stat_nsec_found=yes
 fi
 
+ac_fn_c_check_member "$LINENO" "struct sockaddr_in6" "sin6_len" "ac_cv_member_struct_sockaddr_in6_sin6_len" "#include <netinet/in.h>
+"
+if test "x$ac_cv_member_struct_sockaddr_in6_sin6_len" = xyes
+then :
+
+printf "%s\n" "#define HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN 1" >>confdefs.h
+
+
+fi
+ac_fn_c_check_member "$LINENO" "struct sockaddr_in" "sin_len" "ac_cv_member_struct_sockaddr_in_sin_len" "#include <netinet/in.h>
+"
+if test "x$ac_cv_member_struct_sockaddr_in_sin_len" = xyes
+then :
+
+printf "%s\n" "#define HAVE_STRUCT_SOCKADDR_IN_SIN_LEN 1" >>confdefs.h
+
+
+fi
+
 
 if test "${stat_nsec_found}" != yes; then
 	{ printf "%s\n" "$as_me:${as_lineno-$LINENO}: WARNING: Cannot determine nanosecond field of struct stat" >&5

configure.ac

@@ -853,6 +853,7 @@ AC_C_VOLATILE
 AC_CHECK_TYPES([ptrdiff_t])
 stat_nsec_found=no
 AC_CHECK_MEMBERS([struct stat.st_mtim, struct stat.st_mtimensec, struct stat.st_mtimespec], [stat_nsec_found=yes], [], [[#include <sys/stat.h>]])
+AC_CHECK_MEMBERS([struct sockaddr_in6.sin6_len, struct sockaddr_in.sin_len], [], [], [[#include <netinet/in.h>]])
 
 if test "${stat_nsec_found}" != yes; then
 	AC_MSG_WARN(Cannot determine nanosecond field of struct stat)

include/asterisk/autoconfig.h.in

@@ -1055,6 +1055,12 @@
 /* Define to 1 if 'ifr_ifru.ifru_hwaddr' is a member of 'struct ifreq'. */
 #undef HAVE_STRUCT_IFREQ_IFR_IFRU_IFRU_HWADDR
 
+/* Define to 1 if 'sin6_len' is a member of 'struct sockaddr_in6'. */
+#undef HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN
+
+/* Define to 1 if 'sin_len' is a member of 'struct sockaddr_in'. */
+#undef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
+
 /* Define to 1 if 'uid' is a member of 'struct sockpeercred'. */
 #undef HAVE_STRUCT_SOCKPEERCRED_UID
 

res/res_pjproject.c

@@ -560,6 +560,9 @@ int ast_sockaddr_from_pj_sockaddr(struct ast_sockaddr *addr, const pj_sockaddr *
 {
 	if (pjaddr->addr.sa_family == pj_AF_INET()) {
 		struct sockaddr_in *sin = (struct sockaddr_in *) &addr->ss;
+#if defined(HAVE_STRUCT_SOCKADDR_IN_SIN_LEN)
+		sin->sin_len = sizeof(struct sockaddr_in);
+#endif
 		sin->sin_family = AF_INET;
 #if defined(HAVE_PJPROJECT_BUNDLED) && !defined(HAVE_PJPROJECT_BUNDLED_OOT)
 		sin->sin_addr = pjaddr->ipv4.sin_addr;
@@ -571,6 +574,9 @@ int ast_sockaddr_from_pj_sockaddr(struct ast_sockaddr *addr, const pj_sockaddr *
 		addr->len = sizeof(struct sockaddr_in);
 	} else if (pjaddr->addr.sa_family == pj_AF_INET6()) {
 		struct sockaddr_in6 *sin = (struct sockaddr_in6 *) &addr->ss;
+#if defined(HAVE_STRUCT_SOCKADDR_IN6_SIN6_LEN)
+		sin->sin6_len = sizeof(struct sockaddr_in6);
+#endif
 		sin->sin6_family   = AF_INET6;
 		sin->sin6_port     = pjaddr->ipv6.sin6_port;
 		sin->sin6_flowinfo = pjaddr->ipv6.sin6_flowinfo;