Make translate_packet take a fd instead of a tun header.

This will make it easier to use separate fds for reading and
writing in a future change.

Bug: 15340961
Change-Id: I5b081b05765cae0488ac599be5738ce9737cae41
diff --git a/translate.h b/translate.h
index 6d4f126..46e178b 100644
--- a/translate.h
+++ b/translate.h
@@ -60,8 +60,7 @@
                      const struct iphdr *old_header);
 
 // Translate and send packets.
-void translate_packet(const struct tun_data *tunnel, struct tun_pi *tun_header,
-                      const uint8_t *packet, size_t packetsize);
+void translate_packet(int fd, int to_ipv6, const uint8_t *packet, size_t packetsize);
 
 // Translate IPv4 and IPv6 packets.
 int ipv4_packet(clat_packet out, clat_packet_index pos, const uint8_t *packet, size_t len);