| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Date: Fri, 27 Jul 2012 10:06:15 +0400
From: Pavel Emelyanov <xemul@...allels.com>
To: Stephen Hemminger <shemminger@...ux-foundation.org>,
Linux Netdev List <netdev@...r.kernel.org>
Subject: Re: [PATCH 2/2] iproute: Add route showdump command (v2)
On 07/27/2012 09:03 AM, Pavel Emelyanov wrote:
> As you know, the save/restore pair for routes works in a very simple and
> elegant manner -- on save the raw kernel rtnl stream is just put into a
> file, on restore the _very_ _same_ messages are pushed back to the kernel.
>
> Is the same trick possible to save and restore the addresses (the ip
> addr command) as well? Or the RTM_GETADDR messages cannot be just read
> from and written back to the network stack in a generic case?
I mean something like the below, just put the RTM_GETADDR stream into a
file and push it back into the kernel as is. It worked for me in trivial
cases, but is this approach correct generically?
Log:
iproute: Add ability to save, restore and show the interfaces' addresses
Implementation is similar to the ip route {save|restore|showdump} one.
Signed-off-by: Pavel Emelyanov <xemul@...allels.com>
---
diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index 37deda5..6788544 100644
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -34,6 +34,11 @@
#include "ll_map.h"
#include "ip_common.h"
+enum {
+ IPADD_LIST,
+ IPADD_FLUSH,
+ IPADD_SAVE,
+};
static struct
{
@@ -65,8 +70,9 @@ static void usage(void)
fprintf(stderr, "Usage: ip addr {add|change|replace} IFADDR dev STRING [ LIFETIME ]\n");
fprintf(stderr, " [ CONFFLAG-LIST ]\n");
fprintf(stderr, " ip addr del IFADDR dev STRING\n");
- fprintf(stderr, " ip addr {show|flush} [ dev STRING ] [ scope SCOPE-ID ]\n");
+ fprintf(stderr, " ip addr {show|save|flush} [ dev STRING ] [ scope SCOPE-ID ]\n");
fprintf(stderr, " [ to PREFIX ] [ FLAG-LIST ] [ label PATTERN ]\n");
+ fprintf(stderr, " ip addr {showdump|restore}\n");
fprintf(stderr, "IFADDR := PREFIX | ADDR peer PREFIX\n");
fprintf(stderr, " [ broadcast ADDR ] [ anycast ADDR ]\n");
fprintf(stderr, " [ label STRING ] [ scope SCOPE-ID ]\n");
@@ -768,6 +774,99 @@ static int store_nlmsg(const struct sockaddr_nl *who, struct nlmsghdr *n,
return 0;
}
+static __u32 ipadd_dump_magic = 0x47361222;
+
+static int ipadd_save_prep(void)
+{
+ int ret;
+
+ if (isatty(STDOUT_FILENO)) {
+ fprintf(stderr, "Not sending binary stream to stdout\n");
+ return -1;
+ }
+
+ ret = write(STDOUT_FILENO, &ipadd_dump_magic, sizeof(ipadd_dump_magic));
+ if (ret != sizeof(ipadd_dump_magic)) {
+ fprintf(stderr, "Can't write magic to dump file\n");
+ return -1;
+ }
+
+ return 0;
+}
+
+static int ipadd_dump_check_magic(void)
+{
+ int ret;
+ __u32 magic = 0;
+
+ if (isatty(STDIN_FILENO)) {
+ fprintf(stderr, "Can't restore addr dump from a terminal\n");
+ return -1;
+ }
+
+ ret = fread(&magic, sizeof(magic), 1, stdin);
+ if (magic != ipadd_dump_magic) {
+ fprintf(stderr, "Magic mismatch (%d elems, %x magic)\n", ret, magic);
+ return -1;
+ }
+
+ return 0;
+}
+
+static int save_nlmsg(const struct sockaddr_nl *who, struct nlmsghdr *n,
+ void *arg)
+{
+ int ret;
+
+ ret = write(STDOUT_FILENO, n, n->nlmsg_len);
+ if ((ret > 0) && (ret != n->nlmsg_len)) {
+ fprintf(stderr, "Short write while saving nlmsg\n");
+ ret = -EIO;
+ }
+
+ return ret == n->nlmsg_len ? 0 : ret;
+}
+
+static int show_handler(const struct sockaddr_nl *nl, struct nlmsghdr *n, void *arg)
+{
+ struct ifaddrmsg *ifa = NLMSG_DATA(n);
+
+ printf("if%d:\n", ifa->ifa_index);
+ print_addrinfo(NULL, n, stdout);
+ return 0;
+}
+
+static int ipaddr_showdump(void)
+{
+ if (ipadd_dump_check_magic())
+ exit(-1);
+
+ exit(rtnl_from_file(stdin, &show_handler, NULL));
+}
+
+static int restore_handler(const struct sockaddr_nl *nl, struct nlmsghdr *n, void *arg)
+{
+ int ret;
+
+ n->nlmsg_flags |= NLM_F_REQUEST | NLM_F_CREATE | NLM_F_ACK;
+
+ ll_init_map(&rth);
+
+ ret = rtnl_talk(&rth, n, 0, 0, n);
+ if ((ret < 0) && (errno == EEXIST))
+ ret = 0;
+
+ return ret;
+}
+
+static int ipaddr_restore(void)
+{
+ if (ipadd_dump_check_magic())
+ exit(-1);
+
+ exit(rtnl_from_file(stdin, &restore_handler, NULL));
+}
+
static void free_nlmsg_chain(struct nlmsg_chain *info)
{
struct nlmsg_list *l, *n;
@@ -902,7 +1001,7 @@ static int ipaddr_flush(void)
return 1;
}
-static int ipaddr_list_or_flush(int argc, char **argv, int flush)
+static int ipaddr_list_flush_or_save(int argc, char **argv, int action)
{
struct nlmsg_chain linfo = { NULL, NULL};
struct nlmsg_chain ainfo = { NULL, NULL};
@@ -918,7 +1017,7 @@ static int ipaddr_list_or_flush(int argc, char **argv, int flush)
filter.group = INIT_NETDEV_GROUP;
- if (flush) {
+ if (action == IPADD_FLUSH) {
if (argc <= 0) {
fprintf(stderr, "Flush requires arguments.\n");
@@ -1005,9 +1104,26 @@ static int ipaddr_list_or_flush(int argc, char **argv, int flush)
}
}
- if (flush)
+ if (action == IPADD_FLUSH)
return ipaddr_flush();
+ if (action == IPADD_SAVE) {
+ if (ipadd_save_prep())
+ exit(1);
+
+ if (rtnl_wilddump_request(&rth, preferred_family, RTM_GETADDR) < 0) {
+ perror("Cannot send dump request");
+ exit(1);
+ }
+
+ if (rtnl_dump_filter(&rth, save_nlmsg, stdout) < 0) {
+ fprintf(stderr, "Save terminated\n");
+ exit(1);
+ }
+
+ exit(0);
+ }
+
if (rtnl_wilddump_request(&rth, preferred_family, RTM_GETLINK) < 0) {
perror("Cannot send dump request");
exit(1);
@@ -1055,7 +1171,7 @@ int ipaddr_list_link(int argc, char **argv)
{
preferred_family = AF_PACKET;
do_link = 1;
- return ipaddr_list_or_flush(argc, argv, 0);
+ return ipaddr_list_flush_or_save(argc, argv, IPADD_LIST);
}
void ipaddr_reset_filter(int oneline)
@@ -1271,7 +1387,7 @@ static int ipaddr_modify(int cmd, int flags, int argc, char **argv)
int do_ipaddr(int argc, char **argv)
{
if (argc < 1)
- return ipaddr_list_or_flush(0, NULL, 0);
+ return ipaddr_list_flush_or_save(0, NULL, IPADD_LIST);
if (matches(*argv, "add") == 0)
return ipaddr_modify(RTM_NEWADDR, NLM_F_CREATE|NLM_F_EXCL, argc-1, argv+1);
if (matches(*argv, "change") == 0 ||
@@ -1283,9 +1399,15 @@ int do_ipaddr(int argc, char **argv)
return ipaddr_modify(RTM_DELADDR, 0, argc-1, argv+1);
if (matches(*argv, "list") == 0 || matches(*argv, "show") == 0
|| matches(*argv, "lst") == 0)
- return ipaddr_list_or_flush(argc-1, argv+1, 0);
+ return ipaddr_list_flush_or_save(argc-1, argv+1, IPADD_LIST);
if (matches(*argv, "flush") == 0)
- return ipaddr_list_or_flush(argc-1, argv+1, 1);
+ return ipaddr_list_flush_or_save(argc-1, argv+1, IPADD_FLUSH);
+ if (matches(*argv, "save") == 0)
+ return ipaddr_list_flush_or_save(argc-1, argv+1, IPADD_SAVE);
+ if (matches(*argv, "showdump") == 0)
+ return ipaddr_showdump();
+ if (matches(*argv, "restore") == 0)
+ return ipaddr_restore();
if (matches(*argv, "help") == 0)
usage();
fprintf(stderr, "Command \"%s\" is unknown, try \"ip addr help\".\n", *argv);
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Powered by blists - more mailing lists