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>

2 files changed, 37 insertions, 0 deletions

diff --git a/include/linux/phonet.h b/include/linux/phonet.h
index 001c0e679099..3a027f588a4a 100644
--- a/include/linux/phonet.h
+++ b/include/linux/phonet.h
@@ -45,6 +45,38 @@ struct phonethdr {
         __u8    pn_sobj;
 } __attribute__((packed));
 
+/* Common Phonet payload header */
+struct phonetmsg {
+        __u8    pn_trans_id;    /* transaction ID */
+        __u8    pn_msg_id;      /* message type */
+        union {
+                struct {
+                        __u8    pn_submsg_id;   /* message subtype */
+                        __u8    pn_data[5];
+                } base;
+                struct {
+                        __u16   pn_e_res_id;    /* extended resource ID */
+                        __u8    pn_e_submsg_id; /* message subtype */
+                        __u8    pn_e_data[3];
+                } ext;
+        } pn_msg_u;
+};
+#define PN_COMMON_MESSAGE       0xF0
+#define PN_PREFIX               0xE0 /* resource for extended messages */
+#define pn_submsg_id            pn_msg_u.base.pn_submsg_id
+#define pn_e_submsg_id          pn_msg_u.ext.pn_e_submsg_id
+#define pn_e_res_id             pn_msg_u.ext.pn_e_res_id
+#define pn_data                 pn_msg_u.base.pn_data
+#define pn_e_data               pn_msg_u.ext.pn_e_data
+
+/* data for unreachable errors */
+#define PN_COMM_SERVICE_NOT_IDENTIFIED_RESP     0x01
+#define PN_COMM_ISA_ENTITY_NOT_REACHABLE_RESP   0x14
+#define pn_orig_msg_id          pn_data[0]
+#define pn_status               pn_data[1]
+#define pn_e_orig_msg_id        pn_e_data[0]
+#define pn_e_status             pn_e_data[1]
+
 /* Phonet socket address structure */
 struct sockaddr_pn {
         sa_family_t spn_family;
diff --git a/include/net/phonet/phonet.h b/include/net/phonet/phonet.h
index 1c6f7e7d5fea..d4e72508e145 100644
--- a/include/net/phonet/phonet.h
+++ b/include/net/phonet/phonet.h
@@ -60,6 +60,11 @@ static inline struct phonethdr *pn_hdr(struct sk_buff *skb)
         return (struct phonethdr *)skb_network_header(skb);
 }
 
+static inline struct phonetmsg *pn_msg(struct sk_buff *skb)
+{
+        return (struct phonetmsg *)skb_transport_header(skb);
+}
+
 /*
  * Get the other party's sockaddr from received skb. The skb begins
  * with a Phonet header.