map: process dns patterns in the order in which they were defined

Signed-off-by: Felix Fietkau <nbd@nbd.name>

3 files changed, 32 insertions, 15 deletions

diff --git a/dns.c b/dns.c
index 1706238..5d10c6d 100644
--- a/dns.c
+++ b/dns.c
@@ -74,6 +74,7 @@ struct dns_answer {
 
 struct cname_entry {
 	struct avl_node node;
+	uint32_t seq;
 	uint8_t dscp;
 	uint8_t age;
 };
@@ -123,7 +124,7 @@ proto_is_vlan(uint16_t proto)
 }
 
 static void
-cname_cache_set(const char *name, uint8_t dscp)
+cname_cache_set(const char *name, uint8_t dscp, uint32_t seq)
 {
 	struct cname_entry *e;
 
@@ -138,10 +139,11 @@ cname_cache_set(const char *name, uint8_t dscp)
 
 	e->age = 0;
 	e->dscp = dscp;
+	e->seq = seq;
 }
 
 static int
-cname_cache_get(const char *name, uint8_t *dscp)
+cname_cache_get(const char *name, uint8_t *dscp, uint32_t *seq)
 {
 	struct cname_entry *e;
 
@@ -149,12 +151,16 @@ cname_cache_get(const char *name, uint8_t *dscp)
 	if (!e)
 		return -1;
 
-	*dscp = e->dscp;
+	if (*dscp == 0xff || e->seq < *seq) {
+		*dscp = e->dscp;
+		*seq = e->seq;
+	}
+
 	return 0;
 }
 
 static int
-dns_parse_question(struct packet *pkt, const void *hdr, uint8_t *dscp)
+dns_parse_question(struct packet *pkt, const void *hdr, uint8_t *dscp, uint32_t *seq)
 {
 	char qname[MAX_NAME_LEN];
 
@@ -162,14 +168,14 @@ dns_parse_question(struct packet *pkt, const void *hdr, uint8_t *dscp)
 	    !pkt_pull(pkt, sizeof(struct dns_question)))
 		return -1;
 
-	cname_cache_get(qname, dscp);
-	qosify_map_lookup_dns_entry(qname, dscp);
+	cname_cache_get(qname, dscp, seq);
+	qosify_map_lookup_dns_entry(qname, dscp, seq);
 
 	return 0;
 }
 
 static int
-dns_parse_answer(struct packet *pkt, void *hdr, uint8_t *dscp)
+dns_parse_answer(struct packet *pkt, void *hdr, uint8_t *dscp, uint32_t *seq)
 {
 	struct qosify_map_data data = {};
 	char cname[MAX_NAME_LEN];
@@ -196,8 +202,8 @@ dns_parse_answer(struct packet *pkt, void *hdr, uint8_t *dscp)
 			      cname, sizeof(cname)) < 0)
 			return -1;
 
-		qosify_map_lookup_dns_entry(cname, dscp);
-		cname_cache_set(cname, *dscp);
+		qosify_map_lookup_dns_entry(cname, dscp, seq);
+		cname_cache_set(cname, *dscp, *seq);
 
 		return 0;
 	case TYPE_A:
@@ -227,6 +233,7 @@ static void
 qosify_dns_data_cb(struct packet *pkt)
 {
 	struct dns_header *h;
+	uint32_t lookup_seq = 0;
 	uint8_t dscp = 0xff;
 	int i;
 
@@ -241,11 +248,11 @@ qosify_dns_data_cb(struct packet *pkt)
 	if (h->questions != cpu_to_be16(1))
 		return;
 
-	if (dns_parse_question(pkt, h, &dscp))
+	if (dns_parse_question(pkt, h, &dscp, &lookup_seq))
 		return;
 
 	for (i = 0; i < be16_to_cpu(h->answers); i++)
-		if (dns_parse_answer(pkt, h, &dscp))
+		if (dns_parse_answer(pkt, h, &dscp, &lookup_seq))
 			return;
 }
 
diff --git a/map.c b/map.c
index 436de60..e413020 100644
--- a/map.c
+++ b/map.c
@@ -31,6 +31,7 @@ int qosify_map_timeout;
 int qosify_active_timeout;
 struct qosify_config config;
 struct qosify_flow_config flow_config;
+static uint32_t map_dns_seq;
 
 struct qosify_map_file {
 	struct list_head list;
@@ -332,6 +333,9 @@ void __qosify_map_set_entry(struct qosify_map_data *data)
 		bpf_map_update_elem(fd, &data->addr, &val, BPF_ANY);
 	}
 
+	if (data->id == CL_MAP_DNS)
+		e->data.addr.dns.seq = ++map_dns_seq;
+
 	if (add) {
 		if (qosify_map_timeout == ~0 || file) {
 			e->timeout = ~0;
@@ -599,6 +603,7 @@ static void qosify_map_reset_file_entries(void)
 {
 	struct qosify_map_entry *e;
 
+	map_dns_seq = 0;
 	avl_for_each_element(&map_data, e, avl)
 		e->data.file = false;
 }
@@ -710,7 +715,7 @@ void qosify_map_gc(void)
 	uloop_timeout_set(&qosify_map_timer, timeout * 1000);
 }
 
-int qosify_map_lookup_dns_entry(char *host, uint8_t *dscp)
+int qosify_map_lookup_dns_entry(char *host, uint8_t *dscp, uint32_t *seq)
 {
 	struct qosify_map_data data = {
 		.id = CL_MAP_DNS,
@@ -741,7 +746,10 @@ int qosify_map_lookup_dns_entry(char *host, uint8_t *dscp)
 				continue;
 		}
 
-		*dscp = e->data.dscp;
+		if (*dscp == 0xff || e->data.addr.dns.seq < *seq) {
+			*dscp = e->data.dscp;
+			*seq = e->data.addr.dns.seq;
+		}
 		ret = 0;
 	}
 
@@ -753,8 +761,9 @@ int qosify_map_add_dns_host(char *host, const char *addr, const char *type, int
 {
 	struct qosify_map_data data = {};
 	int prev_timeout = qosify_map_timeout;
+	uint32_t lookup_seq = 0;
 
-	if (qosify_map_lookup_dns_entry(host, &data.dscp))
+	if (qosify_map_lookup_dns_entry(host, &data.dscp, &lookup_seq))
 		return 0;
 
 	data.user = true;
diff --git a/qosify.h b/qosify.h
index 4654385..7a598e3 100644
--- a/qosify.h
+++ b/qosify.h
@@ -51,6 +51,7 @@ struct qosify_map_data {
 		struct in_addr ip;
 		struct in6_addr ip6;
 		struct {
+			uint32_t seq;
 			const char *pattern;
 			regex_t regex;
 		} dns;
@@ -89,7 +90,7 @@ void qosify_map_set_dscp_default(enum qosify_map_id id, uint8_t val);
 void qosify_map_reset_config(void);
 void qosify_map_update_config(void);
 void qosify_map_set_classes(struct blob_attr *val);
-int qosify_map_lookup_dns_entry(char *host, uint8_t *dscp);
+int qosify_map_lookup_dns_entry(char *host, uint8_t *dscp, uint32_t *seq);
 int qosify_map_add_dns_host(char *host, const char *addr, const char *type, int ttl);
 int map_parse_flow_config(struct qosify_flow_config *cfg, struct blob_attr *attr,
 			  bool reset);