Phonet: emit errors when a packet cannot be delivered locally
When there is no listener socket for a received packet, send an error
back to the sender.
Signed-off-by: Remi Denis-Courmont <remi.denis-courmont@nokia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/phonet/af_phonet.c b/net/phonet/af_phonet.c
index 50dc258..1d8df6b 100644
--- a/net/phonet/af_phonet.c
+++ b/net/phonet/af_phonet.c
@@ -132,7 +132,7 @@
* Prepends an ISI header and sends a datagram.
*/
static int pn_send(struct sk_buff *skb, struct net_device *dev,
- u16 dst, u16 src, u8 res)
+ u16 dst, u16 src, u8 res, u8 irq)
{
struct phonethdr *ph;
int err;
@@ -163,7 +163,10 @@
skb_reset_mac_header(skb);
skb->pkt_type = PACKET_LOOPBACK;
skb_orphan(skb);
- netif_rx_ni(skb);
+ if (irq)
+ netif_rx(skb);
+ else
+ netif_rx_ni(skb);
err = 0;
} else {
err = dev_hard_header(skb, dev, ntohs(skb->protocol),
@@ -181,6 +184,19 @@
return err;
}
+static int pn_raw_send(const void *data, int len, struct net_device *dev,
+ u16 dst, u16 src, u8 res)
+{
+ struct sk_buff *skb = alloc_skb(MAX_PHONET_HEADER + len, GFP_ATOMIC);
+ if (skb == NULL)
+ return -ENOMEM;
+
+ skb_reserve(skb, MAX_PHONET_HEADER);
+ __skb_put(skb, len);
+ skb_copy_to_linear_data(skb, data, len);
+ return pn_send(skb, dev, dst, src, res, 1);
+}
+
/*
* Create a Phonet header for the skb and send it out. Returns
* non-zero error code if failed. The skb is freed then.
@@ -211,7 +227,7 @@
src = pn_object(saddr, pn_obj(src));
err = pn_send(skb, dev, pn_sockaddr_get_object(target),
- src, pn_sockaddr_get_resource(target));
+ src, pn_sockaddr_get_resource(target), 0);
dev_put(dev);
return err;
@@ -223,6 +239,73 @@
}
EXPORT_SYMBOL(pn_skb_send);
+/* Do not send an error message in response to an error message */
+static inline int can_respond(struct sk_buff *skb)
+{
+ const struct phonethdr *ph;
+ const struct phonetmsg *pm;
+ u8 submsg_id;
+
+ if (!pskb_may_pull(skb, 3))
+ return 0;
+
+ ph = pn_hdr(skb);
+ if (phonet_address_get(skb->dev, ph->pn_rdev) != ph->pn_rdev)
+ return 0; /* we are not the destination */
+ if (ph->pn_res == PN_PREFIX && !pskb_may_pull(skb, 5))
+ return 0;
+
+ ph = pn_hdr(skb); /* re-acquires the pointer */
+ pm = pn_msg(skb);
+ if (pm->pn_msg_id != PN_COMMON_MESSAGE)
+ return 1;
+ submsg_id = (ph->pn_res == PN_PREFIX)
+ ? pm->pn_e_submsg_id : pm->pn_submsg_id;
+ if (submsg_id != PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP &&
+ pm->pn_e_submsg_id != PN_COMM_SERVICE_NOT_IDENTIFIED_RESP)
+ return 1;
+ return 0;
+}
+
+static int send_obj_unreachable(struct sk_buff *rskb)
+{
+ const struct phonethdr *oph = pn_hdr(rskb);
+ const struct phonetmsg *opm = pn_msg(rskb);
+ struct phonetmsg resp;
+
+ memset(&resp, 0, sizeof(resp));
+ resp.pn_trans_id = opm->pn_trans_id;
+ resp.pn_msg_id = PN_COMMON_MESSAGE;
+ if (oph->pn_res == PN_PREFIX) {
+ resp.pn_e_res_id = opm->pn_e_res_id;
+ resp.pn_e_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
+ resp.pn_e_orig_msg_id = opm->pn_msg_id;
+ resp.pn_e_status = 0;
+ } else {
+ resp.pn_submsg_id = PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP;
+ resp.pn_orig_msg_id = opm->pn_msg_id;
+ resp.pn_status = 0;
+ }
+ return pn_raw_send(&resp, sizeof(resp), rskb->dev,
+ pn_object(oph->pn_sdev, oph->pn_sobj),
+ pn_object(oph->pn_rdev, oph->pn_robj),
+ oph->pn_res);
+}
+
+static int send_reset_indications(struct sk_buff *rskb)
+{
+ struct phonethdr *oph = pn_hdr(rskb);
+ static const u8 data[4] = {
+ 0x00 /* trans ID */, 0x10 /* subscribe msg */,
+ 0x00 /* subscription count */, 0x00 /* dummy */
+ };
+
+ return pn_raw_send(data, sizeof(data), rskb->dev,
+ pn_object(oph->pn_sdev, 0x00),
+ pn_object(oph->pn_rdev, oph->pn_robj), 0x10);
+}
+
+
/* packet type functions */
/*
@@ -260,8 +343,13 @@
goto out; /* currently, we cannot be device 0 */
sk = pn_find_sock_by_sa(&sa);
- if (sk == NULL)
+ if (sk == NULL) {
+ if (can_respond(skb)) {
+ send_obj_unreachable(skb);
+ send_reset_indications(skb);
+ }
goto out;
+ }
/* Push data to the socket (or other sockets connected to it). */
return sk_receive_skb(sk, skb, 0);
