From 4a88d2fbe73a64f8f3861089a2b6e3b8e583e71b Mon Sep 17 00:00:00 2001 From: Antonio Quartulli Date: Wed, 13 Jul 2022 00:16:55 +0200 Subject: [PATCH] tun: create tun_name_is_fixed helper This helper encloses the (simple) logic used by OpenVPN to determine if the name passed to --dev has to be considered a fixed interface name or just a pattern. Having a helper is useful because when this logic is required elsewhere, we can just re-use this logic without duplicating the code (which may mean introducing bugs if a future logic change should not update all spots). The logic is actually fairly simple: check if the name contains a number (i.e. tun0). If so, consider the name a fixed device name. While at it make has_digit() accept a signed argument because strings are normally signed (also isdigit() accepts a signed argument). Signed-off-by: Antonio Quartulli Acked-by: Gert Doering Message-Id: <20220712221655.19333-1-a@unstable.cc> URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg24676.html Signed-off-by: Gert Doering --- src/openvpn/buffer.h | 4 ++-- src/openvpn/tun.c | 7 ++++++- src/openvpn/tun.h | 1 + 3 files changed, 9 insertions(+), 3 deletions(-) diff --git a/src/openvpn/buffer.h b/src/openvpn/buffer.h index 231f1b0d4..fece6336d 100644 --- a/src/openvpn/buffer.h +++ b/src/openvpn/buffer.h @@ -356,9 +356,9 @@ strncpynt(char *dest, const char *src, size_t maxlen) /* return true if string contains at least one numerical digit */ static inline bool -has_digit(const unsigned char *src) +has_digit(const char *src) { - unsigned char c; + char c; while ((c = *src++)) { if (isdigit(c)) diff --git a/src/openvpn/tun.c b/src/openvpn/tun.c index e12f0369d..4acccbffb 100644 --- a/src/openvpn/tun.c +++ b/src/openvpn/tun.c @@ -1717,6 +1717,11 @@ read_tun_header(struct tuntap *tt, uint8_t *buf, int len) } #endif /* if defined (TARGET_OPENBSD) || (defined(TARGET_DARWIN) && HAVE_NET_IF_UTUN_H) */ +bool +tun_name_is_fixed(const char *dev) +{ + return has_digit(dev); +} #if !(defined(_WIN32) || defined(TARGET_LINUX)) static void @@ -1771,7 +1776,7 @@ open_tun_generic(const char *dev, const char *dev_type, const char *dev_node, else #endif - if (dynamic && !has_digit((unsigned char *)dev)) + if (dynamic && !tun_name_is_fixed(dev)) { int i; for (i = 0; i < 256; ++i) diff --git a/src/openvpn/tun.h b/src/openvpn/tun.h index 5fcea5903..b7786f466 100644 --- a/src/openvpn/tun.h +++ b/src/openvpn/tun.h @@ -694,5 +694,6 @@ tun_set(struct tuntap *tt, } const char *tun_stat(const struct tuntap *tt, unsigned int rwflags, struct gc_arena *gc); +bool tun_name_is_fixed(const char *dev); #endif /* TUN_H */ -- 2.47.2