sd-ipv4ll: filter out unwanted ARP packets in the kernel

We currently process every ARP packet, but we should only care about the ones
relating to our IP address.

Also rename ipv4ll helpers to apr-utils.[ch], and rework the helpers a bit.

1 files changed, 24 insertions, 45 deletions

diff --git a/src/libsystemd-network/test-ipv4ll.c b/src/libsystemd-network/test-ipv4ll.c
index d60ee98b25..e7447d322f 100644
--- a/src/libsystemd-network/test-ipv4ll.c
+++ b/src/libsystemd-network/test-ipv4ll.c
@@ -31,7 +31,7 @@
 #include "event-util.h"
 
 #include "sd-ipv4ll.h"
-#include "ipv4ll-internal.h"
+#include "arp-util.h"
 
 static bool verbose = false;
 static bool extended = false;
@@ -56,10 +56,10 @@ static void basic_request_handler(sd_ipv4ll *ll, int event, void *userdata) {
         }
 }
 
-int arp_network_send_raw_socket(int fd, const union sockaddr_union *link,
-                                        const struct ether_arp *arp) {
+static int arp_network_send_raw_socket(int fd, int ifindex,
+                                       const struct ether_arp *arp) {
         assert_se(arp);
-        assert_se(link);
+        assert_se(ifindex > 0);
         assert_se(fd >= 0);
 
         if (send(fd, arp, sizeof(struct ether_arp), 0) < 0)
@@ -68,51 +68,35 @@ int arp_network_send_raw_socket(int fd, const union sockaddr_union *link,
         return 0;
 }
 
-int arp_network_bind_raw_socket(int index, union sockaddr_union *link) {
-        if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_NONBLOCK, 0, test_fd) < 0)
-                return -errno;
+int arp_send_probe(int fd, int ifindex,
+                    be32_t pa, const struct ether_addr *ha) {
+        struct ether_arp ea = {};
 
-        return test_fd[0];
-}
+        assert(fd >= 0);
+        assert(ifindex > 0);
+        assert(pa != 0);
+        assert(ha);
 
-static void test_arp_header(struct ether_arp *arp) {
-        assert_se(arp);
-        assert_se(arp->ea_hdr.ar_hrd == htons(ARPHRD_ETHER)); /* HTYPE */
-        assert_se(arp->ea_hdr.ar_pro == htons(ETHERTYPE_IP)); /* PTYPE */
-        assert_se(arp->ea_hdr.ar_hln == ETH_ALEN); /* HLEN */
-        assert_se(arp->ea_hdr.ar_pln == sizeof arp->arp_spa); /* PLEN */
-        assert_se(arp->ea_hdr.ar_op == htons(ARPOP_REQUEST)); /* REQUEST */
+        return arp_network_send_raw_socket(fd, ifindex, &ea);
 }
 
-static void test_arp_probe(void) {
-        struct ether_arp arp;
-        struct ether_addr mac_addr = {
-                .ether_addr_octet = {'A', 'B', 'C', '1', '2', '3'}};
-        be32_t pa = 0x3030;
+int arp_send_announcement(int fd, int ifindex,
+                          be32_t pa, const struct ether_addr *ha) {
+        struct ether_arp ea = {};
 
-        if (verbose)
-                printf("* %s\n", __FUNCTION__);
+        assert(fd >= 0);
+        assert(ifindex > 0);
+        assert(pa != 0);
+        assert(ha);
 
-        arp_packet_probe(&arp, pa, &mac_addr);
-        test_arp_header(&arp);
-        assert_se(memcmp(arp.arp_sha, &mac_addr, ETH_ALEN) == 0);
-        assert_se(memcmp(arp.arp_tpa, &pa, sizeof(pa)) == 0);
+        return arp_network_send_raw_socket(fd, ifindex, &ea);
 }
 
-static void test_arp_announce(void) {
-        struct ether_arp arp;
-        struct ether_addr mac_addr = {
-                .ether_addr_octet = {'A', 'B', 'C', '1', '2', '3'}};
-        be32_t pa = 0x3131;
-
-        if (verbose)
-                printf("* %s\n", __FUNCTION__);
+int arp_network_bind_raw_socket(int index, be32_t address, const struct ether_addr *eth_mac) {
+        if (socketpair(AF_UNIX, SOCK_DGRAM | SOCK_NONBLOCK, 0, test_fd) < 0)
+                return -errno;
 
-        arp_packet_announcement(&arp, pa, &mac_addr);
-        test_arp_header(&arp);
-        assert_se(memcmp(arp.arp_sha, &mac_addr, ETH_ALEN) == 0);
-        assert_se(memcmp(arp.arp_tpa, &pa, sizeof(pa)) == 0);
-        assert_se(memcmp(arp.arp_spa, &pa, sizeof(pa)) == 0);
+        return test_fd[0];
 }
 
 static void test_public_api_setters(sd_event *e) {
@@ -187,18 +171,15 @@ static void test_basic_request(sd_event *e) {
         /* PROBE */
         sd_event_run(e, (uint64_t) -1);
         assert_se(read(test_fd[1], &arp, sizeof(struct ether_arp)) == sizeof(struct ether_arp));
-        test_arp_header(&arp);
 
         if (extended) {
                 /* PROBE */
                 sd_event_run(e, (uint64_t) -1);
                 assert_se(read(test_fd[1], &arp, sizeof(struct ether_arp)) == sizeof(struct ether_arp));
-                test_arp_header(&arp);
 
                 /* PROBE */
                 sd_event_run(e, (uint64_t) -1);
                 assert_se(read(test_fd[1], &arp, sizeof(struct ether_arp)) == sizeof(struct ether_arp));
-                test_arp_header(&arp);
 
                 sd_event_run(e, (uint64_t) -1);
                 assert_se(basic_request_handler_bind == 1);
@@ -218,8 +199,6 @@ int main(int argc, char *argv[]) {
         assert_se(sd_event_new(&e) >= 0);
 
         test_public_api_setters(e);
-        test_arp_probe();
-        test_arp_announce();
         test_basic_request(e);
 
         return 0;