ss: Put filter DB parsing into a separate function

Use a table for database name parsing. The tricky bit is to allow for
association of a (nearly) arbitrary number of DBs with each name.
Luckily the number is not fully arbitrary as there is an upper bound of
MAX_DB items. Since it is not possible to have a variable length
array inside a variable length array, use this knowledge to make the
inner array of fixed length. But since DB values start from zero, an
explicit end entry needs to be present as well, so the inner array has
to be MAX_DB + 1 in size.

Signed-off-by: Phil Sutter <phil@nwl.cc>

diff --git a/misc/ss.c b/misc/ss.c
index 05522176f1e61960d875286d2333f19de32d0221..83e476a0407e553c5722f8d44c4b072e8366394c 100644 (file)
--- a/misc/ss.c
+++ b/misc/ss.c
@@ -340,6 +340,61 @@ static void filter_db_set(struct filter *f, int db, bool enable)
        do_default   = 0;
 }
 
+static int filter_db_parse(struct filter *f, const char *s)
+{
+       const struct {
+               const char *name;
+               int dbs[MAX_DB + 1];
+       } db_name_tbl[] = {
+#define ENTRY(name, ...) { #name, { __VA_ARGS__, MAX_DB } }
+               ENTRY(all, UDP_DB, DCCP_DB, TCP_DB, RAW_DB,
+                          UNIX_ST_DB, UNIX_DG_DB, UNIX_SQ_DB,
+                          PACKET_R_DB, PACKET_DG_DB, NETLINK_DB,
+                          SCTP_DB, VSOCK_ST_DB, VSOCK_DG_DB),
+               ENTRY(inet, UDP_DB, DCCP_DB, TCP_DB, SCTP_DB, RAW_DB),
+               ENTRY(udp, UDP_DB),
+               ENTRY(dccp, DCCP_DB),
+               ENTRY(tcp, TCP_DB),
+               ENTRY(sctp, SCTP_DB),
+               ENTRY(raw, RAW_DB),
+               ENTRY(unix, UNIX_ST_DB, UNIX_DG_DB, UNIX_SQ_DB),
+               ENTRY(unix_stream, UNIX_ST_DB),
+               ENTRY(u_str, UNIX_ST_DB),       /* alias for unix_stream */
+               ENTRY(unix_dgram, UNIX_DG_DB),
+               ENTRY(u_dgr, UNIX_DG_DB),       /* alias for unix_dgram */
+               ENTRY(unix_seqpacket, UNIX_SQ_DB),
+               ENTRY(u_seq, UNIX_SQ_DB),       /* alias for unix_seqpacket */
+               ENTRY(packet, PACKET_R_DB, PACKET_DG_DB),
+               ENTRY(packet_raw, PACKET_R_DB),
+               ENTRY(p_raw, PACKET_R_DB),      /* alias for packet_raw */
+               ENTRY(packet_dgram, PACKET_DG_DB),
+               ENTRY(p_dgr, PACKET_DG_DB),     /* alias for packet_dgram */
+               ENTRY(netlink, NETLINK_DB),
+               ENTRY(vsock, VSOCK_ST_DB, VSOCK_DG_DB),
+               ENTRY(vsock_stream, VSOCK_ST_DB),
+               ENTRY(v_str, VSOCK_ST_DB),      /* alias for vsock_stream */
+               ENTRY(vsock_dgram, VSOCK_DG_DB),
+               ENTRY(v_dgr, VSOCK_DG_DB),      /* alias for vsock_dgram */
+#undef ENTRY
+       };
+       bool enable = true;
+       unsigned int i;
+       const int *dbp;
+
+       if (s[0] == '!') {
+               enable = false;
+               s++;
+       }
+       for (i = 0; i < ARRAY_SIZE(db_name_tbl); i++) {
+               if (strcmp(s, db_name_tbl[i].name))
+                       continue;
+               for (dbp = db_name_tbl[i].dbs; *dbp != MAX_DB; dbp++)
+                       filter_db_set(f, *dbp, enable);
+               return 0;
+       }
+       return -1;
+}
+
 static void filter_af_set(struct filter *f, int af)
 {
        f->states          |= default_afs[af].states;
@@ -4785,66 +4840,9 @@ int main(int argc, char *argv[])
                        }
                        p = p1 = optarg;
                        do {
-                               bool enable = true;
-
                                if ((p1 = strchr(p, ',')) != NULL)
                                        *p1 = 0;
-                               if (p[0] == '!') {
-                                       enable = false;
-                                       p++;
-                               }
-                               if (strcmp(p, "all") == 0) {
-                                       filter_default_dbs(&current_filter, enable);
-                               } else if (strcmp(p, "inet") == 0) {
-                                       filter_db_set(&current_filter, UDP_DB, enable);
-                                       filter_db_set(&current_filter, DCCP_DB, enable);
-                                       filter_db_set(&current_filter, TCP_DB, enable);
-                                       filter_db_set(&current_filter, SCTP_DB, enable);
-                                       filter_db_set(&current_filter, RAW_DB, enable);
-                               } else if (strcmp(p, "udp") == 0) {
-                                       filter_db_set(&current_filter, UDP_DB, enable);
-                               } else if (strcmp(p, "dccp") == 0) {
-                                       filter_db_set(&current_filter, DCCP_DB, enable);
-                               } else if (strcmp(p, "tcp") == 0) {
-                                       filter_db_set(&current_filter, TCP_DB, enable);
-                               } else if (strcmp(p, "sctp") == 0) {
-                                       filter_db_set(&current_filter, SCTP_DB, enable);
-                               } else if (strcmp(p, "raw") == 0) {
-                                       filter_db_set(&current_filter, RAW_DB, enable);
-                               } else if (strcmp(p, "unix") == 0) {
-                                       filter_db_set(&current_filter, UNIX_ST_DB, enable);
-                                       filter_db_set(&current_filter, UNIX_DG_DB, enable);
-                                       filter_db_set(&current_filter, UNIX_SQ_DB, enable);
-                               } else if (strcasecmp(p, "unix_stream") == 0 ||
-                                          strcmp(p, "u_str") == 0) {
-                                       filter_db_set(&current_filter, UNIX_ST_DB, enable);
-                               } else if (strcasecmp(p, "unix_dgram") == 0 ||
-                                          strcmp(p, "u_dgr") == 0) {
-                                       filter_db_set(&current_filter, UNIX_DG_DB, enable);
-                               } else if (strcasecmp(p, "unix_seqpacket") == 0 ||
-                                          strcmp(p, "u_seq") == 0) {
-                                       filter_db_set(&current_filter, UNIX_SQ_DB, enable);
-                               } else if (strcmp(p, "packet") == 0) {
-                                       filter_db_set(&current_filter, PACKET_R_DB, enable);
-                                       filter_db_set(&current_filter, PACKET_DG_DB, enable);
-                               } else if (strcmp(p, "packet_raw") == 0 ||
-                                          strcmp(p, "p_raw") == 0) {
-                                       filter_db_set(&current_filter, PACKET_R_DB, enable);
-                               } else if (strcmp(p, "packet_dgram") == 0 ||
-                                          strcmp(p, "p_dgr") == 0) {
-                                       filter_db_set(&current_filter, PACKET_DG_DB, enable);
-                               } else if (strcmp(p, "netlink") == 0) {
-                                       filter_db_set(&current_filter, NETLINK_DB, enable);
-                               } else if (strcmp(p, "vsock") == 0) {
-                                       filter_db_set(&current_filter, VSOCK_ST_DB, enable);
-                                       filter_db_set(&current_filter, VSOCK_DG_DB, enable);
-                               } else if (strcmp(p, "vsock_stream") == 0 ||
-                                          strcmp(p, "v_str") == 0) {
-                                       filter_db_set(&current_filter, VSOCK_ST_DB, enable);
-                               } else if (strcmp(p, "vsock_dgram") == 0 ||
-                                          strcmp(p, "v_dgr") == 0) {
-                                       filter_db_set(&current_filter, VSOCK_DG_DB, enable);
-                               } else {
+                               if (filter_db_parse(&current_filter, p)) {
                                        fprintf(stderr, "ss: \"%s\" is illegal socket table id\n", p);
                                        usage();
                                }