ppp: send ConfNak with random magic number if magic number in CanfReq is equal to self magic number

1 files changed, 35 insertions, 21 deletions

diff --git a/accel-pppd/ppp/lcp_opt_magic.c b/accel-pppd/ppp/lcp_opt_magic.c
index 4a61ef9..6c0deb5 100644
--- a/accel-pppd/ppp/lcp_opt_magic.c
+++ b/accel-pppd/ppp/lcp_opt_magic.c
@@ -11,6 +11,7 @@
 static struct lcp_option_t *magic_init(struct ppp_lcp_t *lcp);
 static void magic_free(struct ppp_lcp_t *lcp, struct lcp_option_t *opt);
 static int magic_send_conf_req(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr);
+static int magic_send_conf_nak(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr);
 static int magic_recv_conf_req(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr);
 static void magic_print(void (*print)(const char *fmt,...),struct lcp_option_t*, uint8_t *ptr);
 
@@ -22,20 +23,21 @@ struct magic_option_t
 
 static struct lcp_option_handler_t magic_opt_hnd=
 {
-	.init=magic_init,
-	.send_conf_req=magic_send_conf_req,
-	.recv_conf_req=magic_recv_conf_req,
-	.free=magic_free,
-	.print=magic_print,
+	.init = magic_init,
+	.send_conf_req = magic_send_conf_req,
+	.send_conf_nak = magic_send_conf_nak,
+	.recv_conf_req = magic_recv_conf_req,
+	.free = magic_free,
+	.print = magic_print,
 };
 
 static struct lcp_option_t *magic_init(struct ppp_lcp_t *lcp)
 {
-	struct magic_option_t *magic_opt=_malloc(sizeof(*magic_opt));
-	memset(magic_opt,0,sizeof(*magic_opt));
-	magic_opt->magic=random();
-	magic_opt->opt.id=CI_MAGIC;
-	magic_opt->opt.len=6;
+	struct magic_option_t *magic_opt = _malloc(sizeof(*magic_opt));
+	memset(magic_opt, 0, sizeof(*magic_opt));
+	magic_opt->magic = random();
+	magic_opt->opt.id = CI_MAGIC;
+	magic_opt->opt.len = 6;
 
 	lcp->magic = magic_opt->magic;
 
@@ -44,7 +46,7 @@ static struct lcp_option_t *magic_init(struct ppp_lcp_t *lcp)
 
 static void magic_free(struct ppp_lcp_t *lcp, struct lcp_option_t *opt)
 {
-	struct magic_option_t *magic_opt=container_of(opt,typeof(*magic_opt),opt);
+	struct magic_option_t *magic_opt = container_of(opt,typeof(*magic_opt),opt);
 
 	_free(magic_opt);
 }
@@ -52,17 +54,27 @@ static void magic_free(struct ppp_lcp_t *lcp, struct lcp_option_t *opt)
 static int magic_send_conf_req(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr)
 {
 	struct magic_option_t *magic_opt=container_of(opt,typeof(*magic_opt),opt);
-	struct lcp_opt32_t *opt32=(struct lcp_opt32_t*)ptr;
+	struct lcp_opt32_t *opt32 = (struct lcp_opt32_t *)ptr;
 	opt32->hdr.id=CI_MAGIC;
 	opt32->hdr.len=6;
 	opt32->val=htonl(magic_opt->magic);
 	return 6;
 }
 
-static int magic_recv_conf_req(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr)
+static int magic_send_conf_nak(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr)
 {
 	struct magic_option_t *magic_opt=container_of(opt,typeof(*magic_opt),opt);
-	struct lcp_opt32_t *opt32=(struct lcp_opt32_t*)ptr;
+	struct lcp_opt32_t *opt32 = (struct lcp_opt32_t *)ptr;
+	opt32->hdr.id=CI_MAGIC;
+	opt32->hdr.len=6;
+	opt32->val=random();
+	return 6;
+}
+
+static int magic_recv_conf_req(struct ppp_lcp_t *lcp, struct lcp_option_t *opt, uint8_t *ptr)
+{
+	struct magic_option_t *magic_opt = container_of(opt, typeof(*magic_opt), opt);
+	struct lcp_opt32_t *opt32 = (struct lcp_opt32_t *)ptr;
 
 	/*if (!ptr)
 		return LCP_OPT_NAK;*/
@@ -70,19 +82,21 @@ static int magic_recv_conf_req(struct ppp_lcp_t *lcp, struct lcp_option_t *opt,
 	if (opt32->hdr.len != 6)
 		return LCP_OPT_REJ;
 
-	if (magic_opt->magic==ntohl(opt32->val))
-	{
-		log_ppp_error("loop detected");
-		return -1;
-	}
+	if (magic_opt->magic == ntohl(opt32->val))
+		return LCP_OPT_NAK;
+
 	return LCP_OPT_ACK;
 }
 
 static void magic_print(void (*print)(const char *fmt,...),struct lcp_option_t *opt, uint8_t *ptr)
 {
-	struct magic_option_t *magic_opt=container_of(opt,typeof(*magic_opt),opt);
+	struct magic_option_t *magic_opt = container_of(opt, typeof(*magic_opt), opt);
+	struct lcp_opt32_t *opt32 = (struct lcp_opt32_t *)ptr;
 
-	print("<magic %04x>",magic_opt->magic);
+	if (ptr)
+		print("<magic %04x>", ntohl(opt32->val));
+	else
+		print("<magic %04x>", magic_opt->magic);
 }
 
 static void __init magic_opt_init()