change ppp_decode to store the length of the decoded frame, so that
if we have a packet with a protocol we don't understand, we can send
Protocol-Reject packets. Modify ppp_cp code to add support for sending
Protocol-Reject packet.
---
gatchat/ppp.c | 29 +++++++++++++++++++----------
gatchat/ppp.h | 1 +
gatchat/ppp_cp.c | 42 ++++++++++++++++++++++++++++++++++++++++++
gatchat/ppp_cp.h | 2 ++
gatchat/ppp_lcp.c | 5 +++++
5 files changed, 69 insertions(+), 10 deletions(-)
diff --git a/gatchat/ppp.c b/gatchat/ppp.c
index d771c3f..f93b52d 100644
--- a/gatchat/ppp.c
+++ b/gatchat/ppp.c
@@ -39,6 +39,11 @@
#define PPPINITFCS16 0xffff /* Initial FCS value */
#define PPPGOODFCS16 0xf0b8 /* Good final FCS value */
+struct frame_buffer {
+ gsize len;
+ guint8 bytes[0];
+};
+
static GList *packet_handlers = NULL;
void ppp_register_packet_handler(struct ppp_packet_handler *handler)
@@ -185,12 +190,12 @@ static gint is_proto_handler(gconstpointer a,
gconstpointer b)
static void ppp_recv(GAtPPP *ppp)
{
GList *list;
- guint8 *frame;
+ struct frame_buffer *frame;
/* pop frames off of receive queue */
while ((frame = g_queue_pop_head(ppp->recv_queue))) {
- guint protocol = ppp_proto(frame);
- guint8 *packet = ppp_info(frame);
+ guint protocol = ppp_proto(frame->bytes);
+ guint8 *packet = ppp_info(frame->bytes);
struct ppp_packet_handler *h;
/*
@@ -203,23 +208,26 @@ static void ppp_recv(GAtPPP *ppp)
if (list) {
h = list->data;
h->handler(h->priv, packet);
- }
+ } else
+ lcp_protocol_reject(ppp->lcp, frame->bytes, frame->len);
g_free(frame);
}
}
/* XXX - Implement PFC and ACFC */
-static guint8 *ppp_decode(GAtPPP *ppp, guint8 *frame)
+static struct frame_buffer *ppp_decode(GAtPPP *ppp, guint8 *frame)
{
guint8 *data;
guint pos = 0;
int i = 0;
int len;
guint16 fcs;
+ struct frame_buffer *fb;
- data = g_try_malloc0(ppp->mru + 10);
- if (!data)
+ fb = g_try_malloc0(sizeof(struct frame_buffer) + ppp->mru + 10);
+ if (!fb)
return NULL;
+ data = fb->bytes;
/* skip the first flag char */
pos++;
@@ -237,6 +245,7 @@ static guint8 *ppp_decode(GAtPPP *ppp, guint8 *frame)
}
len = i;
+ fb->len = len;
/* see if we have a good FCS */
fcs = PPPINITFCS16;
@@ -244,16 +253,16 @@ static guint8 *ppp_decode(GAtPPP *ppp, guint8 *frame)
fcs = ppp_fcs(fcs, data[i]);
if (fcs != PPPGOODFCS16) {
- g_free(data);
+ g_free(fb);
return NULL;
}
- return data;
+ return fb;
}
static void ppp_feed(GAtPPP *ppp, guint8 *data, gsize len)
{
guint pos = 0;
- guint8 *frame;
+ struct frame_buffer *frame;
/* collect bytes until we detect we have received a complete frame */
/* examine the data. If we are at the beginning of a new frame,
diff --git a/gatchat/ppp.h b/gatchat/ppp.h
index 05cd50f..6797603 100644
--- a/gatchat/ppp.h
+++ b/gatchat/ppp.h
@@ -156,6 +156,7 @@ void lcp_open(struct pppcp_data *data);
void lcp_close(struct pppcp_data *data);
void lcp_establish(struct pppcp_data *data);
void lcp_terminate(struct pppcp_data *data);
+void lcp_protocol_reject(struct pppcp_data *lcp, guint8 *packet, gsize len);
void auth_set_credentials(struct auth_data *data, const char *username,
const char *passwd);
void auth_set_proto(struct auth_data *data, guint16 proto, guint8 method);
diff --git a/gatchat/ppp_cp.c b/gatchat/ppp_cp.c
index f83cfba..263fa8b 100644
--- a/gatchat/ppp_cp.c
+++ b/gatchat/ppp_cp.c
@@ -1442,6 +1442,48 @@ static guint8 pppcp_process_discard_request(struct
pppcp_data *data,
return 0;
}
+void pppcp_send_protocol_reject(struct pppcp_data *data,
+ guint8 *rejected_packet, gsize len)
+{
+ struct pppcp_packet *packet;
+ struct ppp_header *ppp_packet = (struct ppp_header *) rejected_packet;
+
+ pppcp_trace(data);
+
+ /*
+ * Protocol-Reject can only be sent when we are in
+ * the OPENED state. If in any other state, silently discard.
+ */
+ if (data->state != OPENED) {
+ g_free(ppp_packet);
+ return;
+ }
+
+ /*
+ * info should contain the old packet info, plus the 16bit
+ * protocol number we are rejecting.
+ */
+ packet = pppcp_packet_new(data, PROTOCOL_REJECT, len);
+
+ /*
+ * Identifier must be changed for each Protocol-Reject sent
+ */
+ packet->identifier = new_identity(data, data->reject_identifier);
+
+ /*
+ * rejected packet should be copied in, but it should be
+ * truncated if it needs to be to comply with mtu requirement
+ */
+ memcpy(packet->data, rejected_packet,
+ (ntohs(packet->length) - CP_HEADER_SZ));
+
+ ppp_transmit(data->ppp, pppcp_to_ppp_packet(packet),
+ ntohs(packet->length));
+
+ pppcp_packet_free(packet);
+
+}
+
/*
* parse the packet and determine which event this packet caused
*/
diff --git a/gatchat/ppp_cp.h b/gatchat/ppp_cp.h
index 69676cd..e326b5e 100644
--- a/gatchat/ppp_cp.h
+++ b/gatchat/ppp_cp.h
@@ -150,3 +150,5 @@ void pppcp_generate_event(struct pppcp_data *data,
enum pppcp_event_type event_type,
gpointer event_data, guint data_len);
void pppcp_process_packet(gpointer priv, guint8 *new_packet);
+void pppcp_send_protocol_reject(struct pppcp_data *data,
+ guint8 *rejected_packet, gsize len);
diff --git a/gatchat/ppp_lcp.c b/gatchat/ppp_lcp.c
index 7206b4b..1ccc3cc 100644
--- a/gatchat/ppp_lcp.c
+++ b/gatchat/ppp_lcp.c
@@ -220,6 +220,11 @@ void lcp_free(struct pppcp_data *lcp)
pppcp_free(lcp);
}
+void lcp_protocol_reject(struct pppcp_data *lcp, guint8 *packet, gsize len)
+{
+ pppcp_send_protocol_reject(lcp, packet, len);
+}
+
struct pppcp_data *lcp_new(GAtPPP *ppp)
{
struct pppcp_data *pppcp;
--
1.6.6.1
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