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-rw-r--r--llmnr-query.c16
-rw-r--r--pkt.h15
2 files changed, 24 insertions, 7 deletions
diff --git a/llmnr-query.c b/llmnr-query.c
index 5de2c6b..996723d 100644
--- a/llmnr-query.c
+++ b/llmnr-query.c
@@ -297,7 +297,6 @@ int main(int argc, char **argv)
FD_ZERO(&rfds);
FD_SET(sock, &rfds);
- /* wait up to one second for a response */
tv.tv_sec = timeout_ms / 1000;
tv.tv_usec = (timeout_ms % 1000) * 1000;
@@ -347,10 +346,14 @@ int main(int argc, char **argv)
name = (char *)pkt_put(p, nl + 1);
}
- type = htons(*(uint16_t *)pkt_put(p, sizeof(type)));
- clss = htons(*(uint16_t *)pkt_put(p, sizeof(clss)));
- ttl = htonl(*(uint32_t *)pkt_put(p, sizeof(ttl)));
- addr_size = htons(*(uint16_t *)pkt_put(p, sizeof(addr_size)));
+ type = htons(pkt_put_extract_u16(p));
+ clss = htons(pkt_put_extract_u16(p));
+
+ if (clss != LLMNR_CLASS_IN)
+ log_warn("Unexpected response class received: %d\n", clss);
+
+ ttl = htonl(pkt_put_extract_u32(p));
+ addr_size = htons(pkt_put_extract_u16(p));
if (addr_size == sizeof(struct in_addr)) {
af = AF_INET;
@@ -361,7 +364,8 @@ int main(int argc, char **argv)
break;
}
- if (!inet_ntop(af, pkt_put(p, addr_size), addr, ARRAY_SIZE(addr)))
+ memcpy(&sst, pkt_put(p, addr_size), addr_size);
+ if (!inet_ntop(af, &sst, addr, ARRAY_SIZE(addr)))
strncpy(addr, "<invalid>", sizeof(addr));
addr[INET6_ADDRSTRLEN] = '\0';
diff --git a/pkt.h b/pkt.h
index bb2b717..70591b5 100644
--- a/pkt.h
+++ b/pkt.h
@@ -1,7 +1,7 @@
/*
* Packet buffer structure and utilities.
*
- * Copyright (C) 2015 Tobias Klauser <tklauser@distanz.ch>
+ * Copyright (C) 2015-2017 Tobias Klauser <tklauser@distanz.ch>
*
* Based on pkt_buff.h from the netsniff-ng toolkit which is:
*
@@ -108,4 +108,17 @@ DEFINE_PKT_PUT(8)
DEFINE_PKT_PUT(16)
DEFINE_PKT_PUT(32)
+/* extract values from struct pkt in an alignment-safe way */
+#define DEFINE_PKT_PUT_EXTRACT(__bitwidth) \
+static inline uint##__bitwidth##_t pkt_put_extract_u##__bitwidth(struct pkt *p) \
+{ \
+ uint##__bitwidth##_t val; \
+ memcpy(&val, pkt_put(p, sizeof(val)), sizeof(val)); \
+ return val; \
+}
+
+DEFINE_PKT_PUT_EXTRACT(8)
+DEFINE_PKT_PUT_EXTRACT(16)
+DEFINE_PKT_PUT_EXTRACT(32)
+
#endif /* PKT_H */