rdma: Add filtering infrastructure

This patch adds general infrastructure to RDMAtool to handle various
filtering options needed for the downstream resource tracking patches.

The infrastructure is generic and stores filters in list of key<->value
entries. There are three types of filters:

1. Numeric - the values are intended to be digits combined with '-' to
mark range and ',' to mark multiple entries, e.g. pid 1-100,234,400-401
is perfectly legit filter to limit process ids.

2. String - the values are consist from strings and "," as a denominator.

3. Link - special case to allow '/' in string to provide link name, e.g.
link mlx4_1/2.

Signed-off-by: Leon Romanovsky <leonro@mellanox.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

rdma/rdma.c

@@ -47,6 +47,7 @@ static int rd_init(struct rd *rd, int argc, char **argv, char *filename)
 	rd->argc = argc;
 	rd->argv = argv;
 	INIT_LIST_HEAD(&rd->dev_map_list);
+	INIT_LIST_HEAD(&rd->filter_list);
 
 	if (rd->json_output) {
 		rd->jw = jsonw_new(stdout);

rdma/rdma.h

@@ -29,6 +29,18 @@
 #define RDMA_BITMAP_ENUM(name, bit_no) RDMA_BITMAP_##name = BIT(bit_no),
 #define RDMA_BITMAP_NAMES(name, bit_no) [bit_no] = #name,
 
+#define MAX_NUMBER_OF_FILTERS 64
+struct filters {
+	char name[32];
+	bool is_number;
+};
+
+struct filter_entry {
+	struct list_head list;
+	char *key;
+	char *value;
+};
+
 struct dev_map {
 	struct list_head list;
 	char *dev_name;
@@ -50,6 +62,7 @@ struct rd {
 	json_writer_t *jw;
 	bool json_output;
 	bool pretty_output;
+	struct list_head filter_list;
 };
 
 struct rd_cmd {
@@ -81,6 +94,13 @@ int rd_argc(struct rd *rd);
  */
 struct dev_map *dev_map_lookup(struct rd *rd, bool allow_port_index);
 
+/*
+ * Filter manipulation
+ */
+int rd_build_filter(struct rd *rd, const struct filters valid_filters[]);
+bool rd_check_is_filtered(struct rd *rd, const char *key, uint32_t val);
+bool rd_check_is_string_filtered(struct rd *rd, const char *key, const char *val);
+bool rd_check_is_key_exist(struct rd *rd, const char *key);
 /*
  * Netlink
  */

rdma/utils.c

@@ -114,6 +114,234 @@ static void dev_map_cleanup(struct rd *rd)
 	}
 }
 
+static int add_filter(struct rd *rd, char *key, char *value,
+		      const struct filters valid_filters[])
+{
+	char cset[] = "1234567890,-";
+	struct filter_entry *fe;
+	bool key_found = false;
+	int idx = 0;
+	int ret;
+
+	fe = calloc(1, sizeof(*fe));
+	if (!fe)
+		return -ENOMEM;
+
+	while (idx < MAX_NUMBER_OF_FILTERS && valid_filters[idx].name) {
+		if (!strcmpx(key, valid_filters[idx].name)) {
+			key_found = true;
+			break;
+		}
+		idx++;
+	}
+	if (!key_found) {
+		pr_err("Unsupported filter option: %s\n", key);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	/*
+	 * Check the filter validity, not optimal, but works
+	 *
+	 * Actually, there are three types of filters
+	 *  numeric - for example PID or QPN
+	 *  string  - for example states
+	 *  link    - user requested to filter on specific link
+	 *            e.g. mlx5_1/1, mlx5_1/-, mlx5_1 ...
+	 */
+	if (valid_filters[idx].is_number &&
+	    strspn(value, cset) != strlen(value)) {
+		pr_err("%s filter accepts \"%s\" characters only\n", key, cset);
+		ret = -EINVAL;
+		goto err;
+	}
+
+	fe->key = strdup(key);
+	fe->value = strdup(value);
+	if (!fe->key || !fe->value) {
+		ret = -ENOMEM;
+		goto err_alloc;
+	}
+
+	for (idx = 0; idx < strlen(fe->value); idx++)
+		fe->value[idx] = tolower(fe->value[idx]);
+
+	list_add_tail(&fe->list, &rd->filter_list);
+	return 0;
+
+err_alloc:
+	free(fe->value);
+	free(fe->key);
+err:
+	free(fe);
+	return ret;
+}
+
+int rd_build_filter(struct rd *rd, const struct filters valid_filters[])
+{
+	int ret = 0;
+	int idx = 0;
+
+	if (!valid_filters || !rd_argc(rd))
+		goto out;
+
+	if (rd_argc(rd) == 1) {
+		pr_err("No filter data was supplied to filter option %s\n", rd_argv(rd));
+		ret = -EINVAL;
+		goto out;
+	}
+
+	if (rd_argc(rd) % 2) {
+		pr_err("There is filter option without data\n");
+		ret = -EINVAL;
+		goto out;
+	}
+
+	while (idx != rd_argc(rd)) {
+		/*
+		 * We can do micro-optimization and skip "dev"
+		 * and "link" filters, but it is not worth of it.
+		 */
+		ret = add_filter(rd, *(rd->argv + idx),
+				 *(rd->argv + idx + 1), valid_filters);
+		if (ret)
+			goto out;
+		idx += 2;
+	}
+
+out:
+	return ret;
+}
+
+bool rd_check_is_key_exist(struct rd *rd, const char *key)
+{
+	struct filter_entry *fe;
+
+	list_for_each_entry(fe, &rd->filter_list, list) {
+		if (!strcmpx(fe->key, key))
+			return true;
+	}
+
+	return false;
+}
+
+/*
+ * Check if string entry is filtered:
+ *  * key doesn't exist -> user didn't request -> not filtered
+ */
+bool rd_check_is_string_filtered(struct rd *rd,
+				 const char *key, const char *val)
+{
+	bool key_is_filtered = false;
+	struct filter_entry *fe;
+	char *p = NULL;
+	char *str;
+
+	list_for_each_entry(fe, &rd->filter_list, list) {
+		if (!strcmpx(fe->key, key)) {
+			/* We found the key */
+			p = strdup(fe->value);
+			key_is_filtered = true;
+			if (!p) {
+				/*
+				 * Something extremely wrong if we fail
+				 * to allocate small amount of bytes.
+				 */
+				pr_err("Found key, but failed to allocate memory to store value\n");
+				return key_is_filtered;
+			}
+
+			/*
+			 * Need to check if value in range
+			 * It can come in the following formats
+			 * and their permutations:
+			 * str
+			 * str1,str2
+			 */
+			str = strtok(p, ",");
+			while (str) {
+				if (strlen(str) == strlen(val) &&
+				    !strcasecmp(str, val)) {
+					key_is_filtered = false;
+					goto out;
+				}
+				str = strtok(NULL, ",");
+			}
+			goto out;
+		}
+	}
+
+out:
+	free(p);
+	return key_is_filtered;
+}
+
+/*
+ * Check if key is filtered:
+ * key doesn't exist -> user didn't request -> not filtered
+ */
+bool rd_check_is_filtered(struct rd *rd, const char *key, uint32_t val)
+{
+	bool key_is_filtered = false;
+	struct filter_entry *fe;
+
+	list_for_each_entry(fe, &rd->filter_list, list) {
+		uint32_t left_val = 0, fe_value = 0;
+		bool range_check = false;
+		char *p = fe->value;
+
+		if (!strcmpx(fe->key, key)) {
+			/* We found the key */
+			key_is_filtered = true;
+			/*
+			 * Need to check if value in range
+			 * It can come in the following formats
+			 * (and their permutations):
+			 * numb
+			 * numb1,numb2
+			 * ,numb1,numb2
+			 * numb1-numb2
+			 * numb1,numb2-numb3,numb4-numb5
+			 */
+			while (*p) {
+				if (isdigit(*p)) {
+					fe_value = strtol(p, &p, 10);
+					if (fe_value == val ||
+					    (range_check && left_val < val &&
+					     val < fe_value)) {
+						key_is_filtered = false;
+						goto out;
+					}
+					range_check = false;
+				} else {
+					if (*p == '-') {
+						left_val = fe_value;
+						range_check = true;
+					}
+					p++;
+				}
+			}
+			goto out;
+		}
+	}
+
+out:
+	return key_is_filtered;
+}
+
+static void filters_cleanup(struct rd *rd)
+{
+	struct filter_entry *fe, *tmp;
+
+	list_for_each_entry_safe(fe, tmp,
+				 &rd->filter_list, list) {
+		list_del(&fe->list);
+		free(fe->key);
+		free(fe->value);
+		free(fe);
+	}
+}
+
 static const enum mnl_attr_data_type nldev_policy[RDMA_NLDEV_ATTR_MAX] = {
 	[RDMA_NLDEV_ATTR_DEV_INDEX] = MNL_TYPE_U32,
 	[RDMA_NLDEV_ATTR_DEV_NAME] = MNL_TYPE_NUL_STRING,
@@ -181,6 +409,7 @@ void rd_free(struct rd *rd)
 		return;
 	free(rd->buff);
 	dev_map_cleanup(rd);
+	filters_cleanup(rd);
 }
 
 int rd_exec_link(struct rd *rd, int (*cb)(struct rd *rd), bool strict_port)