[Babel-users] [PATCH v4 1/2] Rework sysctl writing to only write when needed.
Toke Høiland-Jørgensen
toke at toke.dk
Thu Aug 20 09:29:29 UTC 2015
This reworks the sysctl handling to only write a sysctl if it is not
already the desired value. In addition, the Linux sysctl knobs are now
stored in a lookup table which is looped through, to avoid code
duplication in the setup routine.
Signed-off-by: Toke Høiland-Jørgensen <toke at toke.dk>
---
kernel_netlink.c | 131 +++++++++++++++++--------------------------------------
kernel_socket.c | 23 ++++++----
2 files changed, 56 insertions(+), 98 deletions(-)
diff --git a/kernel_netlink.c b/kernel_netlink.c
index ab63d33..557f7fa 100644
--- a/kernel_netlink.c
+++ b/kernel_netlink.c
@@ -58,10 +58,19 @@ THE SOFTWARE.
int export_table = -1, import_tables[MAX_IMPORT_TABLES], import_table_count = 0;
-static int old_forwarding = -1;
-static int old_ipv4_forwarding = -1;
-static int old_accept_redirects = -1;
-static int old_rp_filter = -1;
+struct sysctl_setting {
+ char *name;
+ int want;
+ int was;
+};
+#define NUM_SYSCTLS 4
+
+static struct sysctl_setting sysctl_settings[NUM_SYSCTLS] = {
+ {"/proc/sys/net/ipv6/conf/all/forwarding", 1, -1},
+ {"/proc/sys/net/ipv4/conf/all/forwarding", 1, -1},
+ {"/proc/sys/net/ipv6/conf/all/accept_redirects", 0, -1},
+ {"/proc/sys/net/ipv4/conf/all/rp_filter", 0, -1},
+};
struct old_if {
char *ifname;
@@ -480,10 +489,12 @@ netlink_send_dump(int type, void *data, int len) {
return 0;
}
+
int
kernel_setup(int setup)
{
- int rc;
+ struct sysctl_setting *s;
+ int i, rc;
if(setup) {
if(export_table < 0)
@@ -503,56 +514,21 @@ kernel_setup(int setup)
}
nl_setup = 1;
- old_forwarding = read_proc("/proc/sys/net/ipv6/conf/all/forwarding");
- if(old_forwarding < 0) {
- perror("Couldn't read forwarding knob.");
- return -1;
- }
-
- rc = write_proc("/proc/sys/net/ipv6/conf/all/forwarding", 1);
- if(rc < 0) {
- perror("Couldn't write forwarding knob.");
- return -1;
- }
-
- old_ipv4_forwarding =
- read_proc("/proc/sys/net/ipv4/conf/all/forwarding");
- if(old_ipv4_forwarding < 0) {
- perror("Couldn't read IPv4 forwarding knob.");
- return -1;
- }
- rc = write_proc("/proc/sys/net/ipv4/conf/all/forwarding", 1);
- if(rc < 0) {
- perror("Couldn't write IPv4 forwarding knob.");
- return -1;
- }
-
-
- old_accept_redirects =
- read_proc("/proc/sys/net/ipv6/conf/all/accept_redirects");
- if(old_accept_redirects < 0) {
- perror("Couldn't read accept_redirects knob.");
- return -1;
- }
-
- rc = write_proc("/proc/sys/net/ipv6/conf/all/accept_redirects", 0);
- if(rc < 0) {
- perror("Couldn't write accept_redirects knob.");
- return -1;
- }
-
- old_rp_filter =
- read_proc("/proc/sys/net/ipv4/conf/all/rp_filter");
- if(old_rp_filter < 0) {
- perror("Couldn't read rp_filter knob.");
- return -1;
- }
-
- rc = write_proc("/proc/sys/net/ipv4/conf/all/rp_filter", 0);
- if(rc < 0) {
- perror("Couldn't write rp_filter knob.");
- return -1;
+ for(i=0; i<NUM_SYSCTLS; i++) {
+ s = &sysctl_settings[i];
+ s->was = read_proc(s->name);
+ if(s->was < 0) {
+ perror("Couldn't read sysctl");
+ return -1;
+ }
+ if(s->was != s->want) {
+ rc = write_proc(s->name, s->want);
+ if(rc < 0) {
+ perror("Couldn't write sysctl");
+ return -1;
+ }
+ }
}
return 1;
@@ -561,46 +537,21 @@ kernel_setup(int setup)
close(dgram_socket);
dgram_socket = -1;
- if(old_forwarding >= 0) {
- rc = write_proc("/proc/sys/net/ipv6/conf/all/forwarding",
- old_forwarding);
- if(rc < 0) {
- perror("Couldn't write forwarding knob.\n");
- return -1;
- }
- }
-
- if(old_ipv4_forwarding >= 0) {
- rc = write_proc("/proc/sys/net/ipv4/conf/all/forwarding",
- old_ipv4_forwarding);
- if(rc < 0) {
- perror("Couldn't write IPv4 forwarding knob.\n");
- return -1;
- }
- }
-
- if(old_accept_redirects >= 0) {
- rc = write_proc("/proc/sys/net/ipv6/conf/all/accept_redirects",
- old_accept_redirects);
- if(rc < 0) {
- perror("Couldn't write accept_redirects knob.\n");
- return -1;
- }
- }
+ close(nl_command.sock);
+ nl_command.sock = -1;
+ nl_setup = 0;
- if(old_rp_filter >= 0) {
- rc = write_proc("/proc/sys/net/ipv4/conf/all/rp_filter",
- old_rp_filter);
- if(rc < 0) {
- perror("Couldn't write rp_filter knob.\n");
- return -1;
+ for(i=0; i<NUM_SYSCTLS; i++) {
+ s = &sysctl_settings[i];
+ if(s->was && s->was != s->want) {
+ rc = write_proc(s->name,s->was);
+ if(rc < 0) {
+ perror("Couldn't write sysctl");
+ return -1;
+ }
}
}
- close(nl_command.sock);
- nl_command.sock = -1;
-
- nl_setup = 0;
return 1;
}
diff --git a/kernel_socket.c b/kernel_socket.c
index 739a599..24658d3 100644
--- a/kernel_socket.c
+++ b/kernel_socket.c
@@ -221,10 +221,14 @@ kernel_setup(int setup)
mib[2] = IPPROTO_IPV6;
mib[3] = IPV6CTL_FORWARDING;
datasize = sizeof(old_forwarding);
- if(setup)
- rc = sysctl(mib, 4, &old_forwarding, &datasize,
- &forwarding, datasize);
- else if(old_forwarding >= 0)
+ if(setup) {
+ rc = sysctl(mib, 4, &old_forwarding, &datasize, NULL, 0);
+ if(rc == 0 && old_forwarding != forwarding) {
+ rc = sysctl(mib, 4, &old_forwarding, &datasize,
+ &forwarding, datasize);
+ }
+ }
+ else if(old_forwarding >= 0 && old_forwarding != forwarding)
rc = sysctl(mib, 4, NULL, NULL,
&old_forwarding, datasize);
if(rc == -1) {
@@ -240,10 +244,13 @@ kernel_setup(int setup)
mib[3] = ICMPV6CTL_REDIRACCEPT;
#endif
datasize = sizeof(old_accept_redirects);
- if(setup)
- rc = sysctl(mib, 4, &old_accept_redirects, &datasize,
- &accept_redirects, datasize);
- else if(old_accept_redirects >= 0)
+ if(setup) {
+ rc = sysctl(mib, 4, &old_accept_redirects, &datasize, NULL, 0);
+ if(rc == 0 && old_accept_redirects != accept_redirects) {
+ rc = sysctl(mib, 4, &old_accept_redirects, &datasize,
+ &accept_redirects, datasize);
+ }
+ else if(old_accept_redirects >= 0 && old_accept_redirects != accept_redirects)
rc = sysctl(mib, 4, NULL, NULL,
&old_accept_redirects, datasize);
if(rc == -1) {
--
2.5.0
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