From: Scott Shambarger <devel@shambarger.net>
Date: Tue, 29 Oct 2024 07:52:45 +0000 (-0700)
Subject: linux: ignore source-based routes (#372)
X-Git-Tag: v10.2.0~35
X-Git-Url: http://git.ipfire.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=fa4e1dd57430308f52f04bbe17f93cca224aa32f;p=thirdparty%2Fdhcpcd.git

linux: ignore source-based routes (#372)

Since source-based routes aren't used by dhcpcd, it's best if they
are ignored so that they aren't confused with default routes.
---

diff --git a/src/if-linux.c b/src/if-linux.c
index 53fa48f5..5980574b 100644
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -702,6 +702,27 @@ if_copyrt(struct dhcpcd_ctx *ctx, struct rt *rt, struct nlmsghdr *nlm)
 		case RTA_DST:
 			sa = &rt->rt_dest;
 			break;
+		case RTA_SRC:
+		{
+			union sa_ss ssa;
+			struct sockaddr *psa = (struct sockaddr *)&ssa;
+			socklen_t salen;
+
+			psa->sa_family = rtm->rtm_family;
+			salen = sa_addrlen(psa);
+			memcpy((char *)psa + sa_addroffset(psa),
+			       RTA_DATA(rta), MIN(salen, RTA_PAYLOAD(rta)));
+			/* if ip-route "from" address is not unspecified,
+                           route is source-based, eg:
+                             <dest-net> from <source-net> via ... dev ...
+                           ignore the route as may otherwise appear to overlap
+                           with routes set/removed by dhcpcd */
+			if (!sa_is_unspecified(psa)) {
+				errno = ENOTSUP;
+				return -1;
+			}
+			break;
+		}
 		case RTA_GATEWAY:
 			sa = &rt->rt_gateway;
 			break;