This commit handles the case where there are several messages in the buffer.
This is very useful to some protocols like SOCK_DIAG.
* netlink.c (nlmsg_fetch, nlmsg_next): New functions.
(decode_netlink_msg): New function.
(decode_netlink): Call decode_netlink_msg().
* tests/netlink_parsing.c (send_query): Adapt test.
---
netlink.c | 45 +++++++++++++++++++++++++++++++++++++++++++--
tests/netlink_parsing.c | 8 ++++----
2 files changed, 47 insertions(+), 6 deletions(-)
diff --git a/netlink.c b/netlink.c
index c43f6e7..fecc413 100644
--- a/netlink.c
+++ b/netlink.c
@@ -31,8 +31,34 @@
#include "xlat/netlink_flags.h"
#include "xlat/netlink_types.h"
-void
-decode_netlink(struct tcb *tcp, unsigned long addr, unsigned long size)
+/* since our target is not in the same process, here are some utils for nlmsg
*/
+static int
+nlmsg_fetch(struct tcb *tcp, struct nlmsghdr *nlmsghdr, unsigned long addr,
+ unsigned long len) {
+ if (len < sizeof(struct nlmsghdr)) {
+ if (len != 0)
+ printstr(tcp, addr, len);
+ return 0;
+ }
+
+ if (umove_or_printaddr(tcp, addr, nlmsghdr) == -1)
+ return 0;
+
+ return nlmsghdr->nlmsg_len >= sizeof(struct nlmsghdr) &&
+ nlmsghdr->nlmsg_len <= len;
+}
+
+static unsigned long
+nlmsg_next(struct nlmsghdr *nlmsghdr, unsigned long addr, unsigned long *len) {
+ *len -= NLMSG_ALIGN(nlmsghdr->nlmsg_len);
+
+ return (unsigned long)
+ ((char *)(addr) + NLMSG_ALIGN(nlmsghdr->nlmsg_len));
+}
+
+static void
+decode_netlink_msg(struct tcb *tcp, unsigned long addr,
+ unsigned long size)
{
struct nlmsghdr nlmsghdr;
@@ -62,3 +88,18 @@ decode_netlink(struct tcb *tcp, unsigned long addr, unsigned
long size)
tprints("}");
}
+
+void
+decode_netlink(struct tcb *tcp, unsigned long addr, unsigned long total_size) {
+ struct nlmsghdr nlmsghdr;
+ unsigned long size = total_size;
+
+ for (; nlmsg_fetch(tcp, &nlmsghdr, addr, size);
+ addr = nlmsg_next(&nlmsghdr, addr, &size)) {
+ if (size != total_size)
+ tprints(", ");
+ tprints("{");
+ decode_netlink_msg(tcp, addr, size);
+ tprints("}");
+ }
+}
diff --git a/tests/netlink_parsing.c b/tests/netlink_parsing.c
index 3e7c983..61957cd 100644
--- a/tests/netlink_parsing.c
+++ b/tests/netlink_parsing.c
@@ -61,8 +61,8 @@ send_query(const int fd)
(unsigned) sizeof(req))
perror_msg_and_skip("sendto");
- printf("sendto(%d, {{len=%u, type=NLMSG_NOOP, flags=NLM_F_REQUEST|0x%x"
- ", seq=0, pid=0}, \"abcd\"}, %u, MSG_DONTWAIT, NULL, 0) = %u\n",
+ printf("sendto(%d, {{{len=%u, type=NLMSG_NOOP, flags=NLM_F_REQUEST|0x%x"
+ ", seq=0, pid=0}, \"abcd\"}}, %u, MSG_DONTWAIT, NULL, 0) = %u\n",
fd, (unsigned) sizeof(req), NLM_F_DUMP,
(unsigned) sizeof(req), (unsigned) sizeof(req));
@@ -73,8 +73,8 @@ send_query(const int fd)
(unsigned) sizeof(req.nlh))
perror_msg_and_skip("sendto");
- printf("sendto(%d, {{len=%u, type=NLMSG_NOOP, flags=NLM_F_REQUEST|0x%x"
- ", seq=0, pid=0}}, %u, MSG_DONTWAIT, NULL, 0) = %u\n",
+ printf("sendto(%d, {{{len=%u, type=NLMSG_NOOP, flags=NLM_F_REQUEST|0x%x"
+ ", seq=0, pid=0}}}, %u, MSG_DONTWAIT, NULL, 0) = %u\n",
fd, (unsigned) sizeof(req.nlh), NLM_F_DUMP,
(unsigned) sizeof(req.nlh), (unsigned) sizeof(req.nlh));
--
2.8.3
------------------------------------------------------------------------------
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patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
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