selftests/bpf: Implement get_hw_ring_size function to retrieve current and max interface size

Introduce a new function called get_hw_size that retrieves both the
current and maximum size of the interface and stores this information
in the 'ethtool_ringparam' structure.

Remove ethtool_channels struct from xdp_hw_metadata.c due to redefinition
error. Remove unused linux/if.h include from flow_dissector BPF test to
address CI pipeline failure.
Signed-off-by: Tushar Vyavahare <tushar.vyavahare@intel.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/bpf/20240402114529.545475-4-tushar.vyavahare@intel.com

tools/testing/selftests/bpf/network_helpers.c

@@ -497,3 +497,27 @@ int get_socket_local_port(int sock_fd)
 
 	return -1;
 }
+
+int get_hw_ring_size(char *ifname, struct ethtool_ringparam *ring_param)
+{
+	struct ifreq ifr = {0};
+	int sockfd, err;
+
+	sockfd = socket(AF_INET, SOCK_DGRAM, 0);
+	if (sockfd < 0)
+		return -errno;
+
+	memcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
+
+	ring_param->cmd = ETHTOOL_GRINGPARAM;
+	ifr.ifr_data = (char *)ring_param;
+
+	if (ioctl(sockfd, SIOCETHTOOL, &ifr) < 0) {
+		err = errno;
+		close(sockfd);
+		return -err;
+	}
+
+	close(sockfd);
+	return 0;
+}

tools/testing/selftests/bpf/network_helpers.h

@@ -9,8 +9,11 @@ typedef __u16 __sum16;
 #include <linux/if_packet.h>
 #include <linux/ip.h>
 #include <linux/ipv6.h>
+#include <linux/ethtool.h>
+#include <linux/sockios.h>
 #include <netinet/tcp.h>
 #include <bpf/bpf_endian.h>
+#include <net/if.h>
 
 #define MAGIC_VAL 0x1234
 #define NUM_ITER 100000
@@ -61,6 +64,7 @@ int make_sockaddr(int family, const char *addr_str, __u16 port,
 		  struct sockaddr_storage *addr, socklen_t *len);
 char *ping_command(int family);
 int get_socket_local_port(int sock_fd);
+int get_hw_ring_size(char *ifname, struct ethtool_ringparam *ring_param);
 
 struct nstoken;
 /**

tools/testing/selftests/bpf/prog_tests/flow_dissector.c

@@ -2,7 +2,6 @@
 #include <test_progs.h>
 #include <network_helpers.h>
 #include <error.h>
-#include <linux/if.h>
 #include <linux/if_tun.h>
 #include <sys/uio.h>
 

tools/testing/selftests/bpf/xdp_hw_metadata.c

@@ -495,20 +495,6 @@ static int verify_metadata(struct xsk *rx_xsk, int rxq, int server_fd, clockid_t
 	return 0;
 }
 
-struct ethtool_channels {
-	__u32	cmd;
-	__u32	max_rx;
-	__u32	max_tx;
-	__u32	max_other;
-	__u32	max_combined;
-	__u32	rx_count;
-	__u32	tx_count;
-	__u32	other_count;
-	__u32	combined_count;
-};
-
-#define ETHTOOL_GCHANNELS	0x0000003c /* Get no of channels */
-
 static int rxq_num(const char *ifname)
 {
 	struct ethtool_channels ch = {