On Sun, Aug 18, 2024 at 05:44:55PM +0200, Stefano Brivio wrote:On Fri, 16 Aug 2024 15:39:43 +1000 David Gibson <david(a)gibson.dropbear.id.au> wrote:Fixed.There are a couple of places where we somewhat messily open code formatting an Ethernet like MAC address for display. Add an eth_ntop() helper for this. Signed-off-by: David Gibson <david(a)gibson.dropbear.id.au> --- conf.c | 7 +++---- dhcp.c | 5 ++--- util.c | 19 +++++++++++++++++++ util.h | 3 +++ 4 files changed, 27 insertions(+), 7 deletions(-) diff --git a/conf.c b/conf.c index ed097bdc..830f91a6 100644 --- a/conf.c +++ b/conf.c @@ -921,7 +921,8 @@ pasta_opts: */ static void conf_print(const struct ctx *c) { - char buf4[INET_ADDRSTRLEN], buf6[INET6_ADDRSTRLEN], ifn[IFNAMSIZ]; + char buf4[INET_ADDRSTRLEN], buf6[INET6_ADDRSTRLEN]; + char bufmac[ETH_ADDRSTRLEN], ifn[IFNAMSIZ]; int i; info("Template interface: %s%s%s%s%s", @@ -955,9 +956,7 @@ static void conf_print(const struct ctx *c) info("Namespace interface: %s", c->pasta_ifn); info("MAC:"); - info(" host: %02x:%02x:%02x:%02x:%02x:%02x", - c->mac[0], c->mac[1], c->mac[2], - c->mac[3], c->mac[4], c->mac[5]); + info(" host: %s", eth_ntop(c->mac, bufmac, sizeof(bufmac))); if (c->ifi4) { if (!c->no_dhcp) { diff --git a/dhcp.c b/dhcp.c index aa9f59da..acc5b03e 100644 --- a/dhcp.c +++ b/dhcp.c @@ -276,6 +276,7 @@ static void opt_set_dns_search(const struct ctx *c, size_t max_len) int dhcp(const struct ctx *c, const struct pool *p) { size_t mlen, dlen, offset = 0, opt_len, opt_off = 0; + char macstr[ETH_ADDRSTRLEN]; const struct ethhdr *eh; const struct iphdr *iph; const struct udphdr *uh; @@ -340,9 +341,7 @@ int dhcp(const struct ctx *c, const struct pool *p) return -1; } - info(" from %02x:%02x:%02x:%02x:%02x:%02x", - m->chaddr[0], m->chaddr[1], m->chaddr[2], - m->chaddr[3], m->chaddr[4], m->chaddr[5]); + info(" from %s", eth_ntop(m->chaddr, macstr, sizeof(macstr))); m->yiaddr = c->ip4.addr; mask.s_addr = htonl(0xffffffff << (32 - c->ip4.prefix_len)); diff --git a/util.c b/util.c index 0b414045..892358b1 100644 --- a/util.c +++ b/util.c @@ -676,6 +676,25 @@ const char *sockaddr_ntop(const void *sa, char *dst, socklen_t size) return dst; } +/** eth_ntop() - Convert an Ethernet MAC address to text format + * @mac: MAC address + * @dst: output buffer, minimum ETH_ADDRSTRLEN bytes + * @size: size of buffer at @dstNit: s/output/Output, s/size/SizeYeah, that makes sense. Done. -- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson+ * + * Return: On success, a non-null pointer to @dst, NULL on failure + */ +const char *eth_ntop(const unsigned char *mac, char *dst, size_t size) +{ + int len; + + len = snprintf(dst, size, "%02x:%02x:%02x:%02x:%02x:%02x", + mac[0], mac[1], mac[2], mac[3], mac[4], mac[5]); + if (len < 0 || (size_t)len >= size) + return NULL; + + return dst; +} + /** str_ee_origin() - Convert socket extended error origin to a string * @ee: Socket extended error structure * diff --git a/util.h b/util.h index cb4d181c..c1748074 100644 --- a/util.h +++ b/util.h @@ -215,9 +215,12 @@ static inline const char *af_name(sa_family_t af) #define SOCKADDR_STRLEN MAX(SOCKADDR_INET_STRLEN, SOCKADDR_INET6_STRLEN) +#define ETH_ADDRSTRLEN (ETH_ALEN * 3)The fact that this includes two digits plus separator for all non-last octets of a MAC address, and two digits plus NULL terminator for the last octet, looks a bit subtle to me. Defining this as sizeof("00:11:22:33:44:55") wouldn't scream "off-by-one" as much, to me. Not a strong preference.