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Phonet: emit errors when a packet cannot be delivered locally

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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>
This commit is contained in:
Remi Denis-Courmont 2008-09-22 20:09:13 -07:00 committed by David S. Miller
parent 87ab4e20b4
commit be0c52bfed
3 changed files with 129 additions and 4 deletions
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32
include/linux/phonet.h
View File

@ -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;

5
include/net/phonet/phonet.h
View File

@ -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.

96
net/phonet/af_phonet.c
View File

@ -132,7 +132,7 @@ EXPORT_SYMBOL(phonet_header_ops);
* 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 @@ static int pn_send(struct sk_buff *skb, struct net_device *dev,
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 @@ drop:
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 @@ int pn_skb_send(struct sock *sk, struct sk_buff *skb,
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 @@ drop:
}
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 @@ static int phonet_rcv(struct sk_buff *skb, struct net_device *dev,
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);