Add mtu6 option to override IPv6 MTU

Signed-off-by: Steven Barth <steven@midlink.org>

diff --git a/bridge.c b/bridge.c
index 9da5314..4a0cbe9 100644 (file)
--- a/bridge.c
+++ b/bridge.c
@@ -299,7 +299,7 @@ bridge_member_cb(struct device_user *dev, enum device_event ev)
                         * bridge mtu is set
                         */
                        system_if_apply_settings(&bst->dev, &bst->dev.settings,
-                                                DEV_OPT_MTU);
+                                                DEV_OPT_MTU | DEV_OPT_MTU6);
                }
 
                break;

diff --git a/device.c b/device.c
index dd2823d..1265c86 100644 (file)
--- a/device.c
+++ b/device.c
@@ -34,6 +34,7 @@ static bool default_ps = true;
 static const struct blobmsg_policy dev_attrs[__DEV_ATTR_MAX] = {
        [DEV_ATTR_TYPE] = { .name = "type", .type = BLOBMSG_TYPE_STRING },
        [DEV_ATTR_MTU] = { .name = "mtu", .type = BLOBMSG_TYPE_INT32 },
+       [DEV_ATTR_MTU6] = { .name = "mtu6", .type = BLOBMSG_TYPE_INT32 },
        [DEV_ATTR_MACADDR] = { .name = "macaddr", .type = BLOBMSG_TYPE_STRING },
        [DEV_ATTR_TXQUEUELEN] = { .name = "txqueuelen", .type = BLOBMSG_TYPE_INT32 },
        [DEV_ATTR_ENABLED] = { .name = "enabled", .type = BLOBMSG_TYPE_BOOL },
@@ -154,6 +155,7 @@ device_merge_settings(struct device *dev, struct device_settings *n)
 
        memset(n, 0, sizeof(*n));
        n->mtu = s->flags & DEV_OPT_MTU ? s->mtu : os->mtu;
+       n->mtu6 = s->flags & DEV_OPT_MTU6 ? s->mtu6 : os->mtu6;
        n->txqueuelen = s->flags & DEV_OPT_TXQUEUELEN ?
                s->txqueuelen : os->txqueuelen;
        memcpy(n->macaddr,
@@ -189,6 +191,11 @@ device_init_settings(struct device *dev, struct blob_attr **tb)
                s->flags |= DEV_OPT_MTU;
        }
 
+       if ((cur = tb[DEV_ATTR_MTU6])) {
+               s->mtu6 = blobmsg_get_u32(cur);
+               s->flags |= DEV_OPT_MTU6;
+       }
+
        if ((cur = tb[DEV_ATTR_TXQUEUELEN])) {
                s->txqueuelen = blobmsg_get_u32(cur);
                s->flags |= DEV_OPT_TXQUEUELEN;
@@ -843,6 +850,8 @@ device_dump_status(struct blob_buf *b, struct device *dev)
                device_merge_settings(dev, &st);
                if (st.flags & DEV_OPT_MTU)
                        blobmsg_add_u32(b, "mtu", st.mtu);
+               if (st.flags & DEV_OPT_MTU6)
+                       blobmsg_add_u32(b, "mtu6", st.mtu6);
                if (st.flags & DEV_OPT_MACADDR)
                        blobmsg_add_string(b, "macaddr", format_macaddr(st.macaddr));
                if (st.flags & DEV_OPT_TXQUEUELEN)

diff --git a/device.h b/device.h
index 3001f10..4d84d80 100644 (file)
--- a/device.h
+++ b/device.h
@@ -28,6 +28,7 @@ typedef int (*device_state_cb)(struct device *, bool up);
 enum {
        DEV_ATTR_TYPE,
        DEV_ATTR_MTU,
+       DEV_ATTR_MTU6,
        DEV_ATTR_MACADDR,
        DEV_ATTR_TXQUEUELEN,
        DEV_ATTR_ENABLED,
@@ -80,6 +81,7 @@ enum {
        DEV_OPT_NEIGHREACHABLETIME      = (1 << 9),
        DEV_OPT_RPS                     = (1 << 10),
        DEV_OPT_XPS                     = (1 << 11),
+       DEV_OPT_MTU6            = (1 << 12),
 };
 
 /* events broadcasted to all users of a device */
@@ -123,6 +125,7 @@ struct device_user {
 struct device_settings {
        unsigned int flags;
        unsigned int mtu;
+       unsigned int mtu6;
        unsigned int txqueuelen;
        uint8_t macaddr[6];
        bool ipv6;

diff --git a/interface-ip.c b/interface-ip.c
index aec3892..7f8a451 100644 (file)
--- a/interface-ip.c
+++ b/interface-ip.c
@@ -767,10 +767,11 @@ interface_set_prefix_address(struct device_prefix_assignment *assignment,
                route.metric = iface->metric;
                system_add_route(l3_downlink, &route);
 
-               if (uplink && uplink->l3_dev.dev) {
-                       int mtu = system_update_ipv6_mtu(
-                                       uplink->l3_dev.dev, 0);
-                       if (mtu > 0)
+               if (uplink && uplink->l3_dev.dev && !(l3_downlink->settings.flags & DEV_OPT_MTU6)) {
+                       int mtu = system_update_ipv6_mtu(uplink->l3_dev.dev, 0);
+                       int mtu_old = system_update_ipv6_mtu(l3_downlink, 0);
+
+                       if (mtu > 0 && mtu_old > mtu)
                                system_update_ipv6_mtu(l3_downlink, mtu);
                }
 

diff --git a/system-linux.c b/system-linux.c
index 6dc9acd..b44eb76 100644 (file)
--- a/system-linux.c
+++ b/system-linux.c
@@ -1019,6 +1019,10 @@ system_if_get_settings(struct device *dev, struct device_settings *s)
                s->flags |= DEV_OPT_MTU;
        }
 
+       s->mtu6 = system_update_ipv6_mtu(dev, 0);
+       if (s->mtu6 > 0)
+               s->flags |= DEV_OPT_MTU6;
+
        if (ioctl(sock_ioctl, SIOCGIFTXQLEN, &ifr) == 0) {
                s->txqueuelen = ifr.ifr_qlen;
                s->flags |= DEV_OPT_TXQUEUELEN;
@@ -1114,6 +1118,9 @@ system_if_apply_settings(struct device *dev, struct device_settings *s, unsigned
                if (ioctl(sock_ioctl, SIOCSIFMTU, &ifr) < 0)
                        s->flags &= ~DEV_OPT_MTU;
        }
+       if (s->flags & DEV_OPT_MTU6 & apply_mask) {
+               system_update_ipv6_mtu(dev, s->mtu6);
+       }
        if (s->flags & DEV_OPT_TXQUEUELEN & apply_mask) {
                ifr.ifr_qlen = s->txqueuelen;
                if (ioctl(sock_ioctl, SIOCSIFTXQLEN, &ifr) < 0)
@@ -2163,19 +2170,18 @@ int system_update_ipv6_mtu(struct device *dev, int mtu)
                        dev->ifname);
 
        int fd = open(buf, O_RDWR);
-       ssize_t len = read(fd, buf, sizeof(buf) - 1);
-       if (len < 0)
-               goto out;
 
-       buf[len] = 0;
-       ret = atoi(buf);
+       if (!mtu) {
+               ssize_t len = read(fd, buf, sizeof(buf) - 1);
+               if (len < 0)
+                       goto out;
 
-       if (!mtu || ret <= mtu)
-               goto out;
-
-       lseek(fd, 0, SEEK_SET);
-       if (write(fd, buf, snprintf(buf, sizeof(buf), "%i", mtu)) <= 0)
-               ret = -1;
+               buf[len] = 0;
+               ret = atoi(buf);
+       } else {
+               if (write(fd, buf, snprintf(buf, sizeof(buf), "%i", mtu)) > 0)
+                       ret = mtu;
+       }
 
 out:
        close(fd);