smc dump：add dumpdev subcmd to specify dummy device used for data capture

Makefile

@@ -115,13 +115,13 @@ endif
 %.o: %.c
 	${CCC} ${ALL_CFLAGS} -c $< -o $@
 
-smc: smc.o info.o ueid.o seid.o dev.o linkgroup.o libnetlink.o util.o
+smc: smc.o info.o ueid.o seid.o dev.o linkgroup.o libnetlink.o util.o dumpdev.o
 	${CCC} ${ALL_CFLAGS} ${ALL_LDFLAGS} $^ -o $@
 
-smcd: smcd.o infod.o ueidd.o seidd.o devd.o linkgroupd.o statsd.o libnetlink.o util.o
+smcd: smcd.o infod.o ueidd.o seidd.o devd.o linkgroupd.o statsd.o libnetlink.o util.o dumpdev.o
 	${CCC} ${ALL_CFLAGS} $^ ${ALL_LDFLAGS} -o $@
 
-smcr: smcr.o infor.o ueidr.o seidr.o devr.o linkgroupr.o statsr.o libnetlink.o util.o
+smcr: smcr.o infor.o ueidr.o seidr.o devr.o linkgroupr.o statsr.o libnetlink.o util.o dumpdev.o
 	${CCC} ${ALL_CFLAGS} $^ ${ALL_LDFLAGS} -o $@
 
 smc_pnet: smc_pnet.c smctools_common.h

dumpdev.c

@@ -0,0 +1,208 @@
+#include <ctype.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "smctools_common.h"
+#include "util.h"
+#include "libnetlink.h"
+#include "dumpdev.h"
+
+static int set_cmd = 0;
+static int reset_cmd = 0;
+static int show_cmd = 0;
+
+static char target_ndev[SMC_MAX_DUMP_DEV_LEN + 1] = { 0 };
+
+extern int smc_id;
+extern struct nl_sock *sk;
+
+const struct nla_policy
+smc_gen_dump_ndev_policy[SMC_NLA_DUMP_DEV_MAX + 1] = {
+	[SMC_NLA_DUMP_DEV_UNSPEC]	= { .type = NLA_UNSPEC },
+	[SMC_NLA_DUMP_DEV_NAME]		= { .type = NLA_NUL_STRING },
+};
+
+static void usage(void)
+{
+	fprintf(stderr,
+		"Usage: smc{r|d} dumpdev [show]\n"
+		"       smc{r|d} dumpdev set <dev_name>\n"
+		"       smc{r|d} dumpdev [reset]\n"
+	);
+	exit(-1);
+}
+
+static int gen_nl_dump_ndev_handle(int cmd, char *dev, int (*cb_handler)(struct nl_msg *msg, void *arg))
+{
+	int rc = EXIT_FAILURE, nlmsg_flags = 0;
+	struct nl_msg *msg;
+
+	nl_socket_modify_cb(sk, NL_CB_VALID, NL_CB_CUSTOM, cb_handler, NULL);
+
+	/* Allocate a netlink message and set header information. */
+	msg = nlmsg_alloc();
+	if (!msg) {
+		nl_perror(NLE_NOMEM, "Error");
+		rc = EXIT_FAILURE;
+		goto err;
+	}
+
+	if (cmd == SMC_NETLINK_GET_DUMP_DEV)
+		nlmsg_flags = NLM_F_DUMP;
+
+	if (!genlmsg_put(msg, NL_AUTO_PORT, NL_AUTO_SEQ, smc_id, 0, nlmsg_flags,
+			 cmd, SMC_GENL_FAMILY_VERSION)) {
+		nl_perror(rc, "Error");
+		rc = EXIT_FAILURE;
+		goto err;
+	}
+
+	if (dev && dev[0]) {
+		rc = nla_put_string(msg, SMC_NLA_DUMP_DEV_NAME, dev);
+		if (rc < 0) {
+			nl_perror(rc, "Error");
+			rc = EXIT_FAILURE;
+			goto err;
+		}
+
+	}
+
+	/* Send message */
+	rc = nl_send_auto(sk, msg);
+	if (rc < 0) {
+		nl_perror(rc, "Error");
+		rc = EXIT_FAILURE;
+		goto err;
+	}
+
+	/* Receive reply message, returns number of cb invocations. */
+	rc = nl_recvmsgs_default(sk);
+
+	if (rc < 0) {
+		if (rc == -NLE_OPNOTSUPP) {
+			fprintf(stderr, "Error: operation not supported by kernel\n");
+		} else if (cmd == SMC_NETLINK_SET_DUMP_DEV) {
+			if (rc == -NLE_NODEV) {
+				fprintf(stderr, "Error: specified dump device is not valid\n");
+			} else if (rc == -NLE_NOMEM) {
+				fprintf(stderr, "Error: lack memory to set dump device\n");
+			} else if (rc == -NLE_INVAL) {
+				fprintf(stderr, "Error: lack memory to set dump device\n");
+			} else {
+				fprintf(stderr, "Error: fail to set specified dump device: %d\n", rc);
+			}
+		} else if (cmd == SMC_NETLINK_RESET_DUMP_DEV) {
+			if (rc == -NLE_INVAL) {
+				fprintf(stderr, "Error: smc dump device was not set\n");
+			} else {
+				fprintf(stderr, "Error: resetting specified dump device fail: %d\n", rc);
+			}
+		} else {
+			nl_perror(rc, "Error");
+		}
+		rc = EXIT_FAILURE;
+		goto err;
+	}
+
+	nlmsg_free(msg);
+	return EXIT_SUCCESS;
+err:
+	nlmsg_free(msg);
+	return rc;
+}
+
+static int handle_gen_dump_ndev_reply(struct nl_msg *msg, void *arg)
+{
+	struct nlattr *attrs[SMC_NLA_DUMP_DEV_NAME + 1];
+	struct nlmsghdr *hdr = nlmsg_hdr(msg);
+	int rc = NL_OK;
+
+	if (genlmsg_parse(hdr, 0, attrs, SMC_NLA_DUMP_DEV_NAME,
+			  (struct nla_policy *)smc_gen_dump_ndev_policy) < 0) {
+		fprintf(stderr, "Error: invalid data returned: smc_gen_dump_ndev_policy\n");
+		nl_msg_dump(msg, stderr);
+		return NL_STOP;
+	}
+
+	if (!attrs[SMC_NLA_DUMP_DEV_NAME])
+		return NL_STOP;
+
+	printf("%s\n", nla_get_string(attrs[SMC_NLA_DUMP_DEV_NAME]));
+	return rc;
+}
+
+static void set_ndev(char *dev)
+{
+	if (strlen(dev) > SMC_MAX_DUMP_DEV_LEN) {
+		fprintf(stderr, "Error: Invalid interface specified: interface name is longer than 16 characters\n");
+		exit(-1);
+	}
+	strncpy(target_ndev, dev, SMC_MAX_DUMP_DEV_LEN);
+}
+
+static void handle_cmd_params(int argc, char **argv)
+{
+	if (argc == 0) {
+		show_cmd = 1; /* no object given, so use the default "show" */
+		return;
+	}
+
+	while (1) {
+		if (set_cmd) {
+			set_ndev(argv[0]);
+			break;
+		} else if (contains(argv[0], "help") == 0) {
+			usage();
+		} else if (contains(argv[0], "set") == 0) {
+			set_cmd = 1;
+		} else if (contains(argv[0], "reset") == 0) {
+			reset_cmd = 1;
+			break;
+		} else if (contains(argv[0], "show") == 0) {
+			show_cmd = 1;
+			break;
+		} else {
+			usage();
+		}
+		if (!NEXT_ARG_OK())
+			break;
+		NEXT_ARG();
+	}
+	/* Too many parameters or wrong sequence of parameters */
+	if (NEXT_ARG_OK())
+		usage();
+
+	/* Only single cmd expected */
+	if ((set_cmd + reset_cmd + show_cmd) != 1)
+		usage();
+
+	/* device name required for command */
+	if (!target_ndev[0] && set_cmd)
+		usage();
+}
+
+int invoke_dumpdev(int argc, char **argv, int detail_level)
+{
+	int rc = EXIT_SUCCESS;
+
+	handle_cmd_params(argc, argv);
+
+	if (set_cmd) {
+		rc = gen_nl_dump_ndev_handle(SMC_NETLINK_SET_DUMP_DEV, target_ndev,
+					     handle_gen_dump_ndev_reply);
+	} else if (reset_cmd) {
+		rc = gen_nl_dump_ndev_handle(SMC_NETLINK_RESET_DUMP_DEV, NULL,
+					     handle_gen_dump_ndev_reply);
+	} else if (show_cmd) {
+		rc = gen_nl_dump_ndev_handle(SMC_NETLINK_GET_DUMP_DEV, NULL,
+					     handle_gen_dump_ndev_reply);
+	} else {
+		printf("Error: Unknown command\n"); /* we should never come here ... */
+	}
+
+	return rc;
+}
+

dumpdev.h

@@ -0,0 +1,6 @@
+#ifndef DUMP_DEV_H_
+#define DUMP_DEV_H_
+
+int invoke_dumpdev(int argc, char **argv, int detail_level);
+
+#endif /* UEID_H_ */

smc.c

@@ -32,6 +32,7 @@
 #include "seid.h"
 #include "info.h"
 #include "stats.h"
+#include "dumpdev.h"
 
 static int option_detail = 0;
 #if defined(SMCD)
@@ -53,10 +54,10 @@ static void usage(void)
 	fprintf(stderr,
 		"Usage: %s  [ OPTIONS ] OBJECT {COMMAND | help}\n"
 #if defined(SMCD)
-		"where  OBJECT := {info | linkgroup | device | stats | ueid | seid}\n"
+		"where  OBJECT := {info | linkgroup | device | stats | ueid | seid | dumpdev}\n"
 		"       OPTIONS := {-v[ersion] | -d[etails] | -a[bsolute]}\n", myname);
 #else
-		"where  OBJECT := {info | linkgroup | device | stats | ueid}\n"
+		"where  OBJECT := {info | linkgroup | device | stats | ueid | dumpdev}\n"
 		"       OPTIONS := {-v[ersion] | -d[etails] | -dd[etails] | -a[bsolute]}\n", myname);
 #endif
 }
@@ -79,6 +80,7 @@ static const struct cmd {
 #if defined(SMCD)
 	{ "seid",	invoke_seid },
 #endif
+	{ "dumpdev",	invoke_dumpdev },
 	{ "help",	invoke_help },
 	{ 0 }
 };

smctools_common.h

@@ -37,6 +37,7 @@
 #define SMC_MAX_UEID		8  /* Max number of eids */
 #define SMC_MAX_PORTS		2  /* Max # of ports per ib device */
 #define SMC_PCI_ID_STR_LEN	16 /* Max length of pci id string */
+#define SMC_MAX_DUMP_DEV_LEN	16 /* Max length of dummy device name */
 
 /* Netlink SMC_PNETID attributes */
 enum {
@@ -80,6 +81,9 @@ enum {
 	SMC_NETLINK_DUMP_SEID,
 	SMC_NETLINK_ENABLE_SEID,
 	SMC_NETLINK_DISABLE_SEID,
+	SMC_NETLINK_GET_DUMP_DEV = 19,
+	SMC_NETLINK_SET_DUMP_DEV,
+	SMC_NETLINK_RESET_DUMP_DEV,
 };
 
 /* SMC_GENL_FAMILY top level attributes */
@@ -304,6 +308,14 @@ enum {
 	SMC_NLA_SEID_TABLE_MAX = __SMC_NLA_SEID_TABLE_MAX - 1
 };
 
+/* SMC_NETLINK_DUMP_DEV attributes */
+enum {
+	SMC_NLA_DUMP_DEV_UNSPEC,
+	SMC_NLA_DUMP_DEV_NAME,  /* string */
+	__SMC_NLA_DUMP_DEV_MAX,
+	SMC_NLA_DUMP_DEV_MAX = __SMC_NLA_DUMP_DEV_MAX - 1
+};
+
 /***********************************************************
  * Mimic definitions in kernel/include/uapi/linux/smc_diag.h
  ***********************************************************/