drivers: net: ppp: Fix link-layer address configuration (15048337) · Commits · Wenxi XU / zephyr

Restore setting the ppp link-local address either to CONFIG_PPP_MAC_ADDR or to a random value 00:00:5e:00:53:XX instead of leaving it uninitialized. Recently the memory handling for the link-layer addresses was changed from an approach of copying pointers to managing the memory as a member of the `net_linkaddr` struct (ref ). The piece of code this patch touches however, relied on the use of the pointers to function properly. With the recent change, the MAC address was copied to the new member location before it was even set (either from Kconfig or selected randomly). As a result, the link-layer address was kept initialized to zero, which resulted in a IPv6 address of fe80::ff:fe00:0 which is exactly the link-local EUI-64 representation of the MAC address 00:00:00:00:00:00 (without flipping the "universal/local" bit). Signed-off-by:

Marc Lasch <marc.lasch@husqvarnagroup.com>

drivers/net/ppp.c

+4 −14

Original line number	Diff line number	Diff line
		@@ -974,17 +974,9 @@ static int ppp_driver_init(const struct device *dev)
		return 0;
		}

		static inline struct net_linkaddr ppp_get_mac(struct ppp_driver_context ppp)
		{
		(void)net_linkaddr_set(&ppp->ll_addr, ppp->mac_addr, sizeof(ppp->mac_addr));

		return &ppp->ll_addr;
		}

		static void ppp_iface_init(struct net_if *iface)
		{
		struct ppp_driver_context *ppp = net_if_get_device(iface)->data;
		struct net_linkaddr *ll_addr;

		LOG_DBG("[%p] iface %p", ppp, iface);

		@@ -997,11 +989,6 @@ static void ppp_iface_init(struct net_if *iface)
		ppp->init_done = true;
		ppp->iface = iface;

		/* The mac address is not really used but network interface expects
		* to find one.
		*/
		ll_addr = ppp_get_mac(ppp);

		if (CONFIG_PPP_MAC_ADDR[0] != 0) {
		if (net_bytes_from_str(ppp->mac_addr, sizeof(ppp->mac_addr),
		CONFIG_PPP_MAC_ADDR) < 0) {
		@@ -1018,7 +1005,10 @@ use_random_mac:
		ppp->mac_addr[5] = sys_rand8_get();
		}

		net_if_set_link_addr(iface, ll_addr->addr, ll_addr->len,
		/* The MAC address is not really used, but the network interface expects to find one. */
		(void)net_linkaddr_set(&ppp->ll_addr, ppp->mac_addr, sizeof(ppp->mac_addr));

		net_if_set_link_addr(iface, ppp->ll_addr.addr, ppp->ll_addr.len,
		NET_LINK_ETHERNET);

		if (IS_ENABLED(CONFIG_NET_PPP_CAPTURE)) {

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