heya,
i want to do some wireguard/gretap tunnel - and many of them
somebody told me that for gre there is a limit of 255 per kernel, does this also aply for gretap
and mainly - is there a limit for if i can add to bat0 - since every gretap is a "if"
thx,
fuzzle, freiburg
On Montag, 23. Januar 2017 18:26:59 CET jens wrote:
somebody told me that for gre there is a limit of 255 per kernel, does this also aply for gretap
I've already used over 500 (sry, not 9000) gretap tunnels. And I've just did the same on Linux 4.9 with gre to test the 255 limit for L3.
for i in `seq 1 255`; do echo $i ip link add gre$i type gre local 192.168.2.227 remote 192.168.3.$i ttl 255 dev enp0s31f6 ip link set up dev gre$i
ip link add grex$i type gre local 192.168.2.227 remote 192.168.4.$i ttl 255 dev enp0s31f6 ip link set up dev grex$i done
At least my Linux kernel was not generating any error messages. Maybe this limit was removed already?
and mainly - is there a limit for if i can add to bat0 - since every gretap is a "if"
There is no artificial limit added by batman-adv. But transmitting a lot of broadcasts over 255 virtual links sharing the same physical link might get interesting (independent of batman-adv).
Kind regards, Sven
On 24.01.2017 14:39, Sven Eckelmann wrote:
There is no artificial limit added by batman-adv. But transmitting a lot of broadcasts over 255 virtual links sharing the same physical link might get interesting (independent of batman-adv).
this made me curious , and i modified your script a bit - turns out after the 127. IF you add to batman-adv you get an Error - all 510 gretap links was succesfully build ... # ifconfig |grep gre| wc -l 515 # batctl if|sort|wc -l 127 the error is mainly *Error - can't write to file '/sys/class/net/gre128/batman_adv/mesh_iface': Cannot allocate memory
*removing one previous IF from batman, and adding the next work fine, but than going over 127 is not possible. like this # batctl if del gre127 # batctl if add gre128 and then # batctl if add gre129 (or whatever other if) fails again
script and dmesg are like this , maybe you can explain what happened, in case its important, this is still batman-adv-v14 thx jens
# add one if per 3 seconds and give dmesg output dmesg -w & for i in `seq 1 255`; do ip link add gre$i type gretap local 192.168.99.1 remote 192.168.3.$i ttl 255 dev wg0 ip link set up dev gre$i batctl if add gre$i ip link add grex$i type gretap local 192.168.99.1 remote 192.168.4.$i ttl 255 dev wg0 ip link set up dev grex$i batctl if add grex$i echo -n $(uptime|cut -d"," -f4-) $(ifconfig wg0|grep TX\ p) $i sleep 3 done
|Load average: 0.01, 0.00, 0.00 TX packets 80872676 bytes 43983093228 (40.9 GiB) 126 Error - can't write to file '/sys/class/net/gre127/batman_adv/mesh_iface': Cannot allocate memory [113990.684849] ------------[ cut here ]------------ [113990.684861] WARNING: CPU: 0 PID: 12430 at /build/linux-lIgGMF/linux-4.8.11/mm/slab_common.c:861 kmalloc_slab+0x90/0xa0 [113990.684867] Modules linked in: dm_mod ip_gre ip_tunnel gre xt_hashlimit wireguard(OE) ip6_udp_tunnel udp_tunnel intel_rapl x86_pkg_temp_thermal coretemp crct10dif_pclmul evdev crc32_pclmul pcspkr ghash_clmulni_intel batman_adv(OE) libcrc32c ip_tabl es x_tables autofs4 ext4 crc16 jbd2 crc32c_generic fscrypto ecb mbcache crc32c_intel aesni_intel xen_netfront xen_blkfront aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd [113990.684907] CPU: 0 PID: 12430 Comm: batctl Tainted: G W OE 4.8.0-2-amd64 #1 Debian 4.8.11-1 [113990.684914] 0000000000000200 0000000052b690a8 ffffffff813269f5 0000000000000000 [113990.684921] 0000000000000000 ffffffff8107c16e 0000000002080020 fffffffffffffc00 [113990.684929] ffffffffc017a804 fffffffffffffc00 ffffffffffffff80 fffffffffffffbf8 [113990.684936] Call Trace: [113990.684942] [<ffffffff813269f5>] ? dump_stack+0x5c/0x77 [113990.684947] [<ffffffff8107c16e>] ? __warn+0xbe/0xe0 [113990.684955] [<ffffffffc017a804>] ? batadv_orig_hash_add_if+0x94/0x140 [batman_adv] [113990.684961] [<ffffffff811a7b10>] ? kmalloc_slab+0x90/0xa0 [113990.684966] [<ffffffff811e08c5>] ? __kmalloc+0x25/0x580 [113990.684971] [<ffffffff815ef9d7>] ? _raw_spin_lock_irqsave+0x17/0x39 [113990.684977] [<ffffffff81432c11>] ? _crng_backtrack_protect+0x31/0x70 [113990.684981] [<ffffffff811e0ebc>] ? kmem_cache_alloc_trace+0x9c/0x540 [113990.684986] [<ffffffff814340b7>] ? get_random_bytes+0xe7/0x1c0 [113990.684991] [<ffffffffc017a804>] ? batadv_orig_hash_add_if+0x94/0x140 [batman_adv] [113990.684999] [<ffffffffc01779ac>] ? batadv_hardif_enable_interface+0x1cc/0x2e0 [batman_adv] [113990.685007] [<ffffffffc017f2c2>] ? batadv_store_mesh_iface+0xb2/0x150 [batman_adv] [113990.685013] [<ffffffff8127fa98>] ? kernfs_fop_write+0x118/0x1a0 [113990.685018] [<ffffffff81202303>] ? vfs_write+0xb3/0x1a0 [113990.685022] [<ffffffff812036e2>] ? SyS_write+0x52/0xc0 [113990.685039] [<ffffffff815efa76>] ? system_call_fast_compare_end+0xc/0x96 [113990.685044] ---[ end trace 3e82ace6f98e8470 ]--- [113990.684849] ------------[ cut here ]------------ [113990.684861] WARNING: CPU: 0 PID: 12430 at /build/linux-lIgGMF/linux-4.8.11/mm/slab_common.c:861 kmalloc_slab+0x90/0xa0 [113990.684867] Modules linked in: dm_mod ip_gre ip_tunnel gre xt_hashlimit wireguard(OE) ip6_udp_tunnel udp_tunnel intel_rapl x86_pkg_temp_thermal coretemp crct10dif_pclmul evdev crc32_pclmul pcspkr ghash_clmulni_intel batman_adv(OE) libcrc32c ip_tabl es x_tables autofs4 ext4 crc16 jbd2 crc32c_generic fscrypto ecb mbcache crc32c_intel aesni_intel xen_netfront xen_blkfront aes_x86_64 glue_helper lrw gf128mul ablk_helper cryptd [113990.684907] CPU: 0 PID: 12430 Comm: batctl Tainted: G W OE 4.8.0-2-amd64 #1 Debian 4.8.11-1 [113990.684914] 0000000000000200 0000000052b690a8 ffffffff813269f5 0000000000000000 [113990.684921] 0000000000000000 ffffffff8107c16e 0000000002080020 fffffffffffffc00 [113990.684929] ffffffffc017a804 fffffffffffffc00 ffffffffffffff80 fffffffffffffbf8 [113990.684936] Call Trace: [113990.684942] [<ffffffff813269f5>] ? dump_stack+0x5c/0x77 [113990.684947] [<ffffffff8107c16e>] ? __warn+0xbe/0xe0 [113990.684955] [<ffffffffc017a804>] ? batadv_orig_hash_add_if+0x94/0x140 [batman_adv] [113990.684961] [<ffffffff811a7b10>] ? kmalloc_slab+0x90/0xa0 [113990.684966] [<ffffffff811e08c5>] ? __kmalloc+0x25/0x580 [113990.684971] [<ffffffff815ef9d7>] ? _raw_spin_lock_irqsave+0x17/0x39 [113990.684977] [<ffffffff81432c11>] ? _crng_backtrack_protect+0x31/0x70 [113990.684981] [<ffffffff811e0ebc>] ? kmem_cache_alloc_trace+0x9c/0x540 [113990.684986] [<ffffffff814340b7>] ? get_random_bytes+0xe7/0x1c0 [113990.684991] [<ffffffffc017a804>] ? batadv_orig_hash_add_if+0x94/0x140 [batman_adv] [113990.684999] [<ffffffffc01779ac>] ? batadv_hardif_enable_interface+0x1cc/0x2e0 [batman_adv] [113990.685007] [<ffffffffc017f2c2>] ? batadv_store_mesh_iface+0xb2/0x150 [batman_adv] [113990.685013] [<ffffffff8127fa98>] ? kernfs_fop_write+0x118/0x1a0 [113990.685018] [<ffffffff81202303>] ? vfs_write+0xb3/0x1a0 [113990.685022] [<ffffffff812036e2>] ? SyS_write+0x52/0xc0 [113990.685039] [<ffffffff815efa76>] ? system_call_fast_compare_end+0xc/0x96 [113990.685044] ---[ end trace 3e82ace6f98e8470 ]--- Error - can't write to file '/sys/class/net/gre127/batman_adv/mesh_iface': Cannot allocate memory load average: 0.01, 0.00, 0.00 TX packets 80874265 bytes 43983761422 (40.9 GiB) 127 Error - can't write to file '/sys/class/net/gre128/batman_adv/mesh_iface': Cannot allocate memory|
On Wed, Jan 25, 2017 at 03:21:58AM +0100, jens wrote:
On 24.01.2017 14:39, Sven Eckelmann wrote:
There is no artificial limit added by batman-adv. But transmitting a lot of broadcasts over 255 virtual links sharing the same physical link might get interesting (independent of batman-adv).
this made me curious , and i modified your script a bit - turns out after the 127. IF you add to batman-adv you get an Error - all 510 gretap links was succesfully build ... # ifconfig |grep gre| wc -l 515 # batctl if|sort|wc -l 127 the error is mainly *Error - can't write to file '/sys/class/net/gre128/batman_adv/mesh_iface': Cannot allocate memory
Hi Jens
What sort of machine are you running this on? How much RAM does it have?
My guess is, you are running it on a little box with not much RAM. If you tried again on your desktop with a few Giga byte of RAM, you will get a different limit.
Andrew
b.a.t.m.a.n@lists.open-mesh.org
-
Andrew Lunn -
jens -
Sven Eckelmann