From 10163af3f4eb92a492fa99c95352bf8cd1a05e92 Mon Sep 17 00:00:00 2001 From: "/C=DE/ST=Berlin/L=Berlin/O=Netfilter Project/OU=Development/CN=laforge/emailAddress=laforge@netfilter.org" Date: Mon, 19 Sep 2005 15:00:33 +0000 Subject: Kernels higher than 2.6.10 don't support multiple --to arguments in DNAT and SNAT targets. At present, the error is somewhat vague: # iptables -t nat -A foo -j SNAT --to 1.2.3.4 --to 2.3.4.5 iptables: Invalid argument But if we want current iptables to work with kernels <= 2.6.10, we cannot simply disallow this in all cases. So the below patch adds kernel version checking to iptables, and utilizes it in [DS]NAT. Now, users will see a more informative error: # iptables -t nat -A foo -j SNAT --to 1.2.3.4 --to 2.3.4.5 iptables v1.3.3: Multiple --to-source not supported This generic infrastructure (shamelessly lifted from procps btw) may come in handy in the future for other changes. This fixes bugzilla #367. (Phil Oester) --- extensions/libipt_DNAT.c | 7 +++++++ extensions/libipt_SNAT.c | 7 +++++++ include/iptables.h | 9 +++++++++ iptables.c | 18 ++++++++++++++++++ 4 files changed, 41 insertions(+) diff --git a/extensions/libipt_DNAT.c b/extensions/libipt_DNAT.c index 3b0d146..bdc15eb 100644 --- a/extensions/libipt_DNAT.c +++ b/extensions/libipt_DNAT.c @@ -155,6 +155,13 @@ parse(int c, char **argv, int invert, unsigned int *flags, exit_error(PARAMETER_PROBLEM, "Unexpected `!' after --to-destination"); + if (*flags) { + if (!kernel_version) + get_kernel_version(); + if (kernel_version > LINUX_VERSION(2, 6, 10)) + exit_error(PARAMETER_PROBLEM, + "Multiple --to-destination not supported"); + } *target = parse_to(optarg, portok, info); *flags = 1; return 1; diff --git a/extensions/libipt_SNAT.c b/extensions/libipt_SNAT.c index 7460760..867c9d0 100644 --- a/extensions/libipt_SNAT.c +++ b/extensions/libipt_SNAT.c @@ -155,6 +155,13 @@ parse(int c, char **argv, int invert, unsigned int *flags, exit_error(PARAMETER_PROBLEM, "Unexpected `!' after --to-source"); + if (*flags) { + if (!kernel_version) + get_kernel_version(); + if (kernel_version > LINUX_VERSION(2, 6, 10)) + exit_error(PARAMETER_PROBLEM, + "Multiple --to-source not supported"); + } *target = parse_to(optarg, portok, info); *flags = 1; return 1; diff --git a/include/iptables.h b/include/iptables.h index f0cad8d..fbcf2eb 100644 --- a/include/iptables.h +++ b/include/iptables.h @@ -175,4 +175,13 @@ extern int flush_entries(const ipt_chainlabel chain, int verbose, iptc_handle_t *handle); extern int for_each_chain(int (*fn)(const ipt_chainlabel, int, iptc_handle_t *), int verbose, int builtinstoo, iptc_handle_t *handle); + +/* kernel revision handling */ +extern int kernel_version; +extern void get_kernel_version(void); +#define LINUX_VERSION(x,y,z) (0x10000*(x) + 0x100*(y) + z) +#define LINUX_VERSION_MAJOR(x) (((x)>>16) & 0xFF) +#define LINUX_VERSION_MINOR(x) (((x)>> 8) & 0xFF) +#define LINUX_VERSION_PATCH(x) ( (x) & 0xFF) + #endif /*_IPTABLES_USER_H*/ diff --git a/iptables.c b/iptables.c index 7e8ba59..aec9613 100644 --- a/iptables.c +++ b/iptables.c @@ -39,6 +39,7 @@ #include #include #include +#include #ifndef TRUE #define TRUE 1 @@ -193,6 +194,8 @@ const char *program_version; const char *program_name; char *lib_dir; +int kernel_version; + /* Keeping track of external matches and targets: linked lists. */ struct iptables_match *iptables_matches = NULL; struct iptables_target *iptables_targets = NULL; @@ -1804,6 +1807,21 @@ static void set_revision(char *name, u_int8_t revision) name[IPT_FUNCTION_MAXNAMELEN - 1] = revision; } +void +get_kernel_version(void) { + static struct utsname uts; + int x = 0, y = 0, z = 0; + + if (uname(&uts) == -1) { + fprintf(stderr, "Unable to retrieve kernel version.\n"); + free_opts(1); + exit(1); + } + + sscanf(uts.release, "%d.%d.%d", &x, &y, &z); + kernel_version = LINUX_VERSION(x, y, z); +} + int do_command(int argc, char *argv[], char **table, iptc_handle_t *handle) { struct ipt_entry fw, *e = NULL; -- cgit v1.2.3