pcap_io: introduce init_once helper that is called with priviledges

When using netsniff-ng with dropping priviledges, we have to introduce
another pcap helper function that is called once before we drop the
priviledges. In this function we have to invoke the disc I/O scheduler
policy, because it needs priviledges. Otherwise netsniff-ng will fail
with "Failed to set io prio for pid" on startup, since we're not root
anymore.

Reported-by: Doug Burks <doug.burks@gmail.com>
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/pcap_io.h b/pcap_io.h
index 0784195..e593922 100644
--- a/pcap_io.h
+++ b/pcap_io.h
@@ -115,6 +115,7 @@ enum pcap_mode {
 };
 
 struct pcap_file_ops {
+	void (*init_once_pcap)(void);
 	int (*pull_fhdr_pcap)(int fd, uint32_t *magic, uint32_t *linktype);
 	int (*push_fhdr_pcap)(int fd, uint32_t magic, uint32_t linktype);
 	int (*prepare_access_pcap)(int fd, enum pcap_mode mode, bool jumbo);