For route MTU comparison allow zero MTU to match interface MTU

Because some OS put the interface MTU into the route MTU if the
route does not define its own.

diff --git a/src/dhcpcd.h b/src/dhcpcd.h
index 17aa8d96aebffde6ede23ec25df336c275a5ec35..074ae1ca793d717bd5c7d4082edba46488a4cde9 100644 (file)
--- a/src/dhcpcd.h
+++ b/src/dhcpcd.h
@@ -80,6 +80,7 @@ struct interface {
        uint16_t hwtype; /* ARPHRD_ETHER for example */
        unsigned char hwaddr[HWADDR_LEN];
        uint8_t hwlen;
+       unsigned int mtu;
        unsigned short vlanid;
        unsigned int metric;
        int carrier;

diff --git a/src/if-bsd.c b/src/if-bsd.c
index d184ef84751058766daed24f93a165e58456821e..8af59610cf725cff5243ac32dc3a8a3454f1bcc0 100644 (file)
--- a/src/if-bsd.c
+++ b/src/if-bsd.c
@@ -1252,6 +1252,7 @@ if_ifinfo(struct dhcpcd_ctx *ctx, const struct if_msghdr *ifm)
        if ((ifp = if_findindex(ctx->ifaces, ifm->ifm_index)) == NULL)
                return 0;
 
+       ifp->mtu = if_mtu(ifp);
        link_state = if_carrier(ifp, &ifm->ifm_data);
        dhcpcd_handlecarrier(ifp, link_state, (unsigned int)ifm->ifm_flags);
        return 0;

diff --git a/src/if-linux.c b/src/if-linux.c
index b6317c35d018a76555428f7f50a1573f2615a987..2a105a1125dbc6c7b337eb011645c837e7ba95b9 100644 (file)
--- a/src/if-linux.c
+++ b/src/if-linux.c
@@ -1053,7 +1053,7 @@ link_netlink(struct dhcpcd_ctx *ctx, void *arg, struct nlmsghdr *nlm)
        struct interface *ifp = arg;
        int r;
        size_t len;
-       struct rtattr *rta, *hwaddr;
+       struct rtattr *rta, *hwaddr, *mtu;
        struct ifinfomsg *ifi;
        char ifn[IF_NAMESIZE + 1];
 
@@ -1082,7 +1082,7 @@ link_netlink(struct dhcpcd_ctx *ctx, void *arg, struct nlmsghdr *nlm)
        rta = (void *)((char *)ifi + NLMSG_ALIGN(sizeof(*ifi)));
        len = NLMSG_PAYLOAD(nlm, sizeof(*ifi));
        *ifn = '\0';
-       hwaddr = NULL;
+       hwaddr = mtu = NULL;
 
        for (; RTA_OK(rta, len); rta = RTA_NEXT(rta, len)) {
                switch (rta->rta_type) {
@@ -1098,6 +1098,9 @@ link_netlink(struct dhcpcd_ctx *ctx, void *arg, struct nlmsghdr *nlm)
                case IFLA_ADDRESS:
                        hwaddr = rta;
                        break;
+               case IFLA_MTU:
+                       mtu = rta;
+                       break;
                }
        }
 
@@ -1139,6 +1142,9 @@ link_netlink(struct dhcpcd_ctx *ctx, void *arg, struct nlmsghdr *nlm)
                return 0;
        }
 
+       if (mtu != NULL)
+               ifp->mtu = *(unsigned int *)RTA_DATA(mtu);
+
        /* Re-read hardware address and friends */
        if (!(ifi->ifi_flags & IFF_UP)) {
                void *hwa = hwaddr != NULL ? RTA_DATA(hwaddr) : NULL;

diff --git a/src/if-sun.c b/src/if-sun.c
index 7f244b7762a8980655e5adff04b6a7d21c8d7690..cb4849b4fe8ca191622733c6b9ce8b14aa0f906a 100644 (file)
--- a/src/if-sun.c
+++ b/src/if-sun.c
@@ -1059,6 +1059,7 @@ if_ifinfo(struct dhcpcd_ctx *ctx, const struct if_msghdr *ifm)
                state = LINK_UP;
                flags |= IFF_UP;
        }
+       ifp->mtu = if_mtu(ifp);
        dhcpcd_handlecarrier(ifp, state, flags);
        return 0;
 }

diff --git a/src/if.c b/src/if.c
index dea833df93260632d567c54283cb3fea4ffcf768..69c2c4c178842611b5686bddf7c80bd71534f0fa 100644 (file)
--- a/src/if.c
+++ b/src/if.c
@@ -182,6 +182,18 @@ if_setflag(struct interface *ifp, short setflag, short unsetflag)
        return 0;
 }
 
+unsigned int
+if_mtu(struct interface *ifp)
+{
+       struct ifreq ifr = { .ifr_mtu = 0 };
+
+       strlcpy(ifr.ifr_name, ifp->name, sizeof(ifr.ifr_name));
+       if (ioctl(ifp->ctx->pf_inet_fd, SIOCGIFMTU, &ifr) == -1)
+               return 0;
+
+       return (unsigned int)ifr.ifr_mtu;
+}
+
 bool
 if_is_link_up(const struct interface *ifp)
 {
@@ -685,6 +697,7 @@ if_discover(struct dhcpcd_ctx *ctx, struct ifaddrs **ifaddrs,
                        }
                }
 
+               ifp->mtu = if_mtu(ifp);
                ifp->vlanid = if_vlanid(ifp);
 
 #ifdef SIOCGIFPRIORITY

diff --git a/src/if.h b/src/if.h
index 6cb9d7662550538b8a7545c910fc0e859333c187..1872a37bdc919c9bebfa9493b3d129210c19e7de 100644 (file)
--- a/src/if.h
+++ b/src/if.h
@@ -163,6 +163,7 @@ int if_ioctl(struct dhcpcd_ctx *, ioctl_request_t, void *, size_t);
 #define        pioctl(ctx, req, data, len) ioctl((ctx)->pf_inet_fd, (req),(data),(len))
 #endif
 int if_setflag(struct interface *, short, short);
+unsigned int if_mtu(struct interface *);
 #define if_up(ifp) if_setflag((ifp), (IFF_UP | IFF_RUNNING), 0)
 #define if_down(ifp) if_setflag((ifp), 0, IFF_UP);
 bool if_is_link_up(const struct interface *);

diff --git a/src/route.c b/src/route.c
index d56b9d307972c08777bc9294fbb9cb4c34c16e34..bbc7bfd7faedc3ac94af86844158fdd6a435e29a 100644 (file)
--- a/src/route.c
+++ b/src/route.c
@@ -506,9 +506,19 @@ rt_recvrt(int cmd, const struct rt *rt, pid_t pid)
 static bool
 rt_cmp_misc(struct rt *nrt, struct rt *ort)
 {
-       /* MTU changed */
+#if defined(__FreeBSD__) || defined(__DragonFly__)
+       /* FreeBSD puts the interface MTU into the route MTU
+        * if the route does not define it's own. */
+       unsigned int nmtu, omtu;
+
+       nmtu = nrt->rt_mtu ? nrt->rt_mtu : nrt->rt_ifp->mtu;
+       omtu = ort->rt_mtu ? ort->rt_mtu : ort->rt_ifp->mtu;
+       if (omtu != nmtu)
+               return false;
+#else
        if (ort->rt_mtu != nrt->rt_mtu)
                return false;
+#endif
 
 #ifdef HAVE_ROUTE_LIFETIME
        uint32_t deviation;