net: mctp: perform source address lookups when we populate our dst

Rather than querying the output device for its address in
mctp_local_output, set up the source address when we're populating the
dst structure. If no address is assigned, use MCTP_ADDR_NULL.

This will allow us more flexibility when routing for NULL-source-eid
cases. For now though, we still reject a NULL source address in the
output path.

We need to update the tests a little, so that addresses are assigned
before we do the dst lookups.

Signed-off-by: Jeremy Kerr <jk@codeconstruct.com.au>
Link: https://patch.msgid.link/20260331-dev-mctp-null-eids-v1-1-b4d047372eaf@codeconstruct.com.au
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

diff --git a/include/net/mctp.h b/include/net/mctp.h
index c3207ce98f07fcbb436e968d503bc45666794fdc..e1e0a69afdcef7f0924523757010e75ea53e8e7c 100644 (file)
--- a/include/net/mctp.h
+++ b/include/net/mctp.h
@@ -270,6 +270,7 @@ struct mctp_dst {
        struct mctp_dev *dev;
        unsigned int mtu;
        mctp_eid_t nexthop;
+       mctp_eid_t saddr;
 
        /* set for direct addressing */
        unsigned char halen;

diff --git a/net/mctp/route.c b/net/mctp/route.c
index 021e04f1ea7c950af4c4e21d7afbc8c98d093186..f6a88e668e68a8431e58ccc46e7ebb7bf2303f71 100644 (file)
--- a/net/mctp/route.c
+++ b/net/mctp/route.c
@@ -880,6 +880,21 @@ static bool mctp_rt_compare_exact(struct mctp_route *rt1,
                rt1->max == rt2->max;
 }
 
+static mctp_eid_t mctp_dev_saddr(struct mctp_dev *dev)
+{
+       mctp_eid_t addr = MCTP_ADDR_NULL;
+       unsigned long flags;
+
+       spin_lock_irqsave(&dev->addrs_lock, flags);
+       if (dev->num_addrs) {
+               /* use the outbound interface's first address as our source */
+               addr = dev->addrs[0];
+       }
+       spin_unlock_irqrestore(&dev->addrs_lock, flags);
+
+       return addr;
+}
+
 /* must only be called on a direct route, as the final output hop */
 static void mctp_dst_from_route(struct mctp_dst *dst, mctp_eid_t eid,
                                unsigned int mtu, struct mctp_route *route)
@@ -892,6 +907,7 @@ static void mctp_dst_from_route(struct mctp_dst *dst, mctp_eid_t eid,
                dst->mtu = min(dst->mtu, mtu);
        dst->halen = 0;
        dst->output = route->output;
+       dst->saddr = mctp_dev_saddr(route->dev);
 }
 
 int mctp_dst_from_extaddr(struct mctp_dst *dst, struct net *net, int ifindex,
@@ -924,6 +940,7 @@ int mctp_dst_from_extaddr(struct mctp_dst *dst, struct net *net, int ifindex,
        dst->halen = halen;
        dst->output = mctp_dst_output;
        dst->nexthop = 0;
+       dst->saddr = mctp_dev_saddr(dev);
        memcpy(dst->haddr, haddr, halen);
 
        rc = 0;
@@ -958,6 +975,7 @@ int mctp_route_lookup(struct net *net, unsigned int dnet,
 {
        const unsigned int max_depth = 32;
        unsigned int depth, mtu = 0;
+       struct mctp_dst dst_tmp;
        int rc = -EHOSTUNREACH;
 
        rcu_read_lock();
@@ -978,9 +996,15 @@ int mctp_route_lookup(struct net *net, unsigned int dnet,
                        mtu = mtu ?: rt->mtu;
 
                if (rt->dst_type == MCTP_ROUTE_DIRECT) {
-                       if (dst)
-                               mctp_dst_from_route(dst, daddr, mtu, rt);
-                       rc = 0;
+                       mctp_dst_from_route(&dst_tmp, daddr, mtu, rt);
+                       /* we need a source address */
+                       if (dst_tmp.saddr == MCTP_ADDR_NULL) {
+                               mctp_dst_release(&dst_tmp);
+                       } else {
+                               if (dst)
+                                       *dst = dst_tmp;
+                               rc = 0;
+                       }
                        break;
 
                } else if (rt->dst_type == MCTP_ROUTE_GATEWAY) {
@@ -1116,26 +1140,15 @@ int mctp_local_output(struct sock *sk, struct mctp_dst *dst,
        struct mctp_sock *msk = container_of(sk, struct mctp_sock, sk);
        struct mctp_sk_key *key;
        struct mctp_hdr *hdr;
-       unsigned long flags;
        unsigned int netid;
-       mctp_eid_t saddr;
-       int rc;
+       int rc = 0;
        u8 tag;
 
        KUNIT_STATIC_STUB_REDIRECT(mctp_local_output, sk, dst, skb, daddr,
                                   req_tag);
 
-       rc = -ENODEV;
-
-       spin_lock_irqsave(&dst->dev->addrs_lock, flags);
-       if (dst->dev->num_addrs == 0) {
+       if (dst->saddr == MCTP_ADDR_NULL)
                rc = -EHOSTUNREACH;
-       } else {
-               /* use the outbound interface's first address as our source */
-               saddr = dst->dev->addrs[0];
-               rc = 0;
-       }
-       spin_unlock_irqrestore(&dst->dev->addrs_lock, flags);
        netid = READ_ONCE(dst->dev->net);
 
        if (rc)
@@ -1146,8 +1159,8 @@ int mctp_local_output(struct sock *sk, struct mctp_dst *dst,
                        key = mctp_lookup_prealloc_tag(msk, netid, daddr,
                                                       req_tag, &tag);
                else
-                       key = mctp_alloc_local_tag(msk, netid, saddr, daddr,
-                                                  false, &tag);
+                       key = mctp_alloc_local_tag(msk, netid, dst->saddr,
+                                                  daddr, false, &tag);
 
                if (IS_ERR(key)) {
                        rc = PTR_ERR(key);
@@ -1174,7 +1187,7 @@ int mctp_local_output(struct sock *sk, struct mctp_dst *dst,
        hdr = mctp_hdr(skb);
        hdr->ver = 1;
        hdr->dest = daddr;
-       hdr->src = saddr;
+       hdr->src = dst->saddr;
 
        /* route output functions consume the skb, even on error */
        return mctp_do_fragment_route(dst, skb, dst->mtu, tag);

diff --git a/net/mctp/test/route-test.c b/net/mctp/test/route-test.c
index 61c989c43ec09c9e105de4e51b295d07bb93d6da..639b7c41c2a233fa78f789d0ef25b87a15fb702b 100644 (file)
--- a/net/mctp/test/route-test.c
+++ b/net/mctp/test/route-test.c
@@ -174,7 +174,9 @@ static void mctp_rx_input_test_to_desc(const struct mctp_rx_input_test *t,
 KUNIT_ARRAY_PARAM(mctp_rx_input, mctp_rx_input_tests,
                  mctp_rx_input_test_to_desc);
 
-/* set up a local dev, route on EID 8, and a socket listening on type 0 */
+/* set up a local dev (with addr 8), route on EID 8, and a socket listening on
+ * type 0
+ */
 static void __mctp_route_test_init(struct kunit *test,
                                   struct mctp_test_dev **devp,
                                   struct mctp_dst *dst,
@@ -191,6 +193,10 @@ static void __mctp_route_test_init(struct kunit *test,
        if (netid != MCTP_NET_ANY)
                WRITE_ONCE(dev->mdev->net, netid);
 
+       dev->mdev->addrs = kmalloc_objs(u8, 1, GFP_KERNEL);
+       dev->mdev->num_addrs = 1;
+       dev->mdev->addrs[0] = 8;
+
        mctp_test_dst_setup(test, dst, dev, 68);
 
        rc = sock_create_kern(&init_net, AF_MCTP, SOCK_DGRAM, 0, &sock);
@@ -928,11 +934,6 @@ static void mctp_test_flow_init(struct kunit *test,
         */
        __mctp_route_test_init(test, &dev, dst, sock, MCTP_NET_ANY);
 
-       /* Assign a single EID. ->addrs is freed on mctp netdev release */
-       dev->mdev->addrs = kmalloc(sizeof(u8), GFP_KERNEL);
-       dev->mdev->num_addrs = 1;
-       dev->mdev->addrs[0] = 8;
-
        skb = alloc_skb(len + sizeof(struct mctp_hdr) + 1, GFP_KERNEL);
        KUNIT_ASSERT_TRUE(test, skb);
        __mctp_cb(skb);
@@ -1058,8 +1059,6 @@ static void mctp_test_route_output_key_create(struct kunit *test)
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
        WRITE_ONCE(dev->mdev->net, netid);
 
-       mctp_test_dst_setup(test, &dst, dev, 68);
-
        rc = sock_create_kern(&init_net, AF_MCTP, SOCK_DGRAM, 0, &sock);
        KUNIT_ASSERT_EQ(test, rc, 0);
 
@@ -1067,6 +1066,8 @@ static void mctp_test_route_output_key_create(struct kunit *test)
        dev->mdev->num_addrs = 1;
        dev->mdev->addrs[0] = src_eid;
 
+       mctp_test_dst_setup(test, &dst, dev, 68);
+
        skb = alloc_skb(sizeof(struct mctp_hdr) + 1 + len, GFP_KERNEL);
        KUNIT_ASSERT_TRUE(test, skb);
        __mctp_cb(skb);
@@ -1165,7 +1166,7 @@ static void mctp_test_route_gw_lookup(struct kunit *test)
        struct mctp_test_dev *dev;
        int rc;
 
-       dev = mctp_test_create_dev();
+       dev = mctp_test_create_dev_with_addr(8);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
 
        /* 8 (local) -> 10 (gateway) via 9 (direct) */
@@ -1195,7 +1196,7 @@ static void mctp_test_route_gw_loop(struct kunit *test)
        struct mctp_test_dev *dev;
        int rc;
 
-       dev = mctp_test_create_dev();
+       dev = mctp_test_create_dev_with_addr(8);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
 
        /* two routes using each other as the gw */
@@ -1254,7 +1255,7 @@ static void mctp_test_route_gw_mtu(struct kunit *test)
        unsigned int netid;
        int rc;
 
-       dev = mctp_test_create_dev();
+       dev = mctp_test_create_dev_with_addr(8);
        KUNIT_ASSERT_NOT_ERR_OR_NULL(test, dev);
        dev->ndev->mtu = mtus->dev;
        mdev = dev->mdev;

diff --git a/net/mctp/test/utils.c b/net/mctp/test/utils.c
index 97afe8cd2b05c9f047c4a6e8c9fb1b4496183cfe..2f79f8c1a2b44beb4917a9b92ffd72955a3a03c6 100644 (file)
--- a/net/mctp/test/utils.c
+++ b/net/mctp/test/utils.c
@@ -80,6 +80,26 @@ struct mctp_test_dev *mctp_test_create_dev(void)
        return __mctp_test_create_dev(0, NULL);
 }
 
+struct mctp_test_dev *mctp_test_create_dev_with_addr(mctp_eid_t addr)
+{
+       struct mctp_test_dev *dev;
+
+       dev = __mctp_test_create_dev(0, NULL);
+       if (!dev)
+               return NULL;
+
+       dev->mdev->addrs = kmalloc_objs(u8, 1, GFP_KERNEL);
+       if (!dev->mdev->addrs) {
+               mctp_test_destroy_dev(dev);
+               return NULL;
+       }
+
+       dev->mdev->num_addrs = 1;
+       dev->mdev->addrs[0] = 8;
+
+       return dev;
+}
+
 struct mctp_test_dev *mctp_test_create_dev_lladdr(unsigned short lladdr_len,
                                                  const unsigned char *lladdr)
 {
@@ -171,6 +191,8 @@ struct mctp_test_route *mctp_test_create_route_gw(struct net *net,
 void mctp_test_dst_setup(struct kunit *test, struct mctp_dst *dst,
                         struct mctp_test_dev *dev, unsigned int mtu)
 {
+       unsigned long flags;
+
        KUNIT_EXPECT_NOT_ERR_OR_NULL(test, dev);
 
        memset(dst, 0, sizeof(*dst));
@@ -179,6 +201,11 @@ void mctp_test_dst_setup(struct kunit *test, struct mctp_dst *dst,
        __mctp_dev_get(dst->dev->dev);
        dst->mtu = mtu;
        dst->output = mctp_test_dst_output;
+       dst->saddr = MCTP_ADDR_NULL;
+       spin_lock_irqsave(&dev->mdev->addrs_lock, flags);
+       if (dev->mdev->num_addrs)
+               dst->saddr = dev->mdev->addrs[0];
+       spin_unlock_irqrestore(&dev->mdev->addrs_lock, flags);
 }
 
 void mctp_test_route_destroy(struct kunit *test, struct mctp_test_route *rt)

diff --git a/net/mctp/test/utils.h b/net/mctp/test/utils.h
index 4cc90c9da4d1bfe9c63b2cac5253f9e09be3b147..47603732e6a570f7bb7e138246071fdbc092f790 100644 (file)
--- a/net/mctp/test/utils.h
+++ b/net/mctp/test/utils.h
@@ -42,6 +42,7 @@ struct mctp_test_bind_setup {
 };
 
 struct mctp_test_dev *mctp_test_create_dev(void);
+struct mctp_test_dev *mctp_test_create_dev_with_addr(mctp_eid_t eid);
 struct mctp_test_dev *mctp_test_create_dev_lladdr(unsigned short lladdr_len,
                                                  const unsigned char *lladdr);
 void mctp_test_destroy_dev(struct mctp_test_dev *dev);