[PATCH] resolv: add IPv6 support to inet_net_pton()
Job Snijders
job@fastly.com
Sun Mar 17 01:23:04 GMT 2024
Dear all,
This is a refresh of a diff I proposed back in December 2022 to add IPv6
support to inet_net_pton().
The starting point of this changeset was OpenBSD's
libc/net/inet_net_pton.c (r1.13) implementation of inet_net_pton_ipv6().
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/lib/libc/net/inet_net_pton.c?annotate=1.13
The OpenBSD implementation was adapted to glibc as following:
1) Use strtol() instead of strtonum()
2) Updated comments
I've tested the changeset on Debian Bookworm.
Your feedback is appreciated!
Kind regards,
Job
Signed-off: Job Snijders <job@fastly.com>
---
resolv/inet_net_pton.c | 78 +++++++++++++++++++++++++++++++++++++++---
1 file changed, 74 insertions(+), 4 deletions(-)
diff --git a/resolv/inet_net_pton.c b/resolv/inet_net_pton.c
index 63a47b7394..27e121c0cb 100644
--- a/resolv/inet_net_pton.c
+++ b/resolv/inet_net_pton.c
@@ -1,4 +1,6 @@
/*
+ * Copyright (c) 2024 Job Snijders <job@fastly.com>
+ * Copyright (c) 2012 by Gilles Chehade <gilles@openbsd.org>
* Copyright (c) 1996,1999 by Internet Software Consortium.
*
* Permission to use, copy, modify, and distribute this software for any
@@ -35,13 +37,16 @@
static int inet_net_pton_ipv4 (const char *src, u_char *dst,
size_t size) __THROW;
+static int inet_net_pton_ipv6 (const char *src, u_char *dst,
+ size_t size) __THROW;
/*
- * static int
+ * int
* inet_net_pton(af, src, dst, size)
- * convert network number from presentation to network format.
- * accepts hex octets, hex strings, decimal octets, and /CIDR.
- * "size" is in bytes and describes "dst".
+ * Convert network number from presentation format to network format.
+ * If "af" is set to AF_INET, accept various formats like hex octets,
+ * hex strings, or decimal octets. If "af" is set to AF_INET6, accept
+ * IPv6 addresses. "size" is in bytes and describes "dst".
* return:
* number of bits, either imputed classfully or specified with /CIDR,
* or -1 if some failure occurred (check errno). ENOENT means it was
@@ -55,6 +60,8 @@ inet_net_pton (int af, const char *src, void *dst, size_t size)
switch (af) {
case AF_INET:
return (inet_net_pton_ipv4(src, dst, size));
+ case AF_INET6:
+ return (inet_net_pton_ipv6(src, dst, size));
default:
__set_errno (EAFNOSUPPORT);
return (-1);
@@ -196,3 +203,66 @@ inet_net_pton_ipv4 (const char *src, u_char *dst, size_t size)
__set_errno (EMSGSIZE);
return (-1);
}
+
+
+/*
+ * Convert an IPv6 prefix from presentation format to network format.
+ * Return the number of bits specified, or -1 as error (check errno).
+ */
+static int
+inet_net_pton_ipv6 (const char *src, u_char *dst, size_t size)
+{
+ struct in6_addr in6;
+ int bits;
+ long lbits;
+ size_t bytes;
+ char buf[INET6_ADDRSTRLEN + sizeof("/128")];
+ char *ep, *sep;
+
+ if (strlcpy(buf, src, sizeof(buf)) >= sizeof(buf)) {
+ errno = EMSGSIZE;
+ return (-1);
+ }
+
+ sep = strchr(buf, '/');
+ if (sep != NULL)
+ *sep++ = '\0';
+
+ if (inet_pton(AF_INET6, buf, &in6) != 1) {
+ __set_errno (ENOENT);
+ return (-1);
+ }
+
+ if (sep == NULL) {
+ bits = 128;
+ goto out;
+ }
+
+ if (sep[0] == '\0' || !isascii(sep[0]) || !isdigit(sep[0])) {
+ __set_errno (ENOENT);
+ return (-1);
+ }
+
+ errno = 0;
+ lbits = strtol(sep, &ep, 10);
+ if (sep[0] == '\0' || *ep != '\0') {
+ __set_errno (ENOENT);
+ return (-1);
+ }
+ if ((errno == ERANGE && (lbits == LONG_MAX || lbits == LONG_MIN))
+ || (lbits > 128 || lbits < 0)) {
+ __set_errno (EMSGSIZE);
+ return (-1);
+ }
+ bits = lbits;
+
+ out:
+ bytes = (bits + 7) / 8;
+ if (bytes > size) {
+ __set_errno (EMSGSIZE);
+ return (-1);
+ }
+
+ memcpy(dst, &in6.s6_addr, bytes);
+ return (bits);
+}
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