diff options
Diffstat (limited to 'batman-adv/patches/0007-batman-adv-decrease-maximum-fragment-size.patch')
| -rw-r--r-- | batman-adv/patches/0007-batman-adv-decrease-maximum-fragment-size.patch | 52 |
1 files changed, 52 insertions, 0 deletions
diff --git a/batman-adv/patches/0007-batman-adv-decrease-maximum-fragment-size.patch b/batman-adv/patches/0007-batman-adv-decrease-maximum-fragment-size.patch new file mode 100644 index 0000000..03d84a0 --- /dev/null +++ b/batman-adv/patches/0007-batman-adv-decrease-maximum-fragment-size.patch @@ -0,0 +1,52 @@ +From: Matthias Schiffer <mschiffer@universe-factory.net> +Date: Wed, 22 Feb 2017 17:25:41 +0100 +Subject: [PATCH] batman-adv: decrease maximum fragment size + +With this patch the maximum fragment size is reduced from 1400 to 1280 +bytes. + +Fragmentation v2 correctly uses the smaller of 1400 and the interface +MTU, thus generally supporting interfaces with an MTU < 1400 bytes, too. + +However, currently "Fragmentation v2" does not support re-fragmentation. +Which means that once a packet is split into two packets of 1400 + x +bytes for instance and the next hop provides an interface with an even +smaller MTU of 1280 bytes, then the larger fragment is lost. + +A maximum fragment size of 1280 bytes is a safer option as this is the +minimum MTU required by IPv6, making interfaces with an MTU < 1280 +rather exotic. + +Regarding performance, this should have no negative impact on unicast +traffic: Having some more bytes in the smaller and some less in the +larger does not change the sum of both fragments. + +Concerning TT, choosing 1280 bytes fragments might result in more TT +messages than necessary when a large network is bridged into batman-adv. +However, the TT overhead in general is marginal due to its reactive +nature, therefore such a performance impact on TT should not be +noticeable for a user. + +Cc: Matthias Schiffer <mschiffer@universe-factory.net> +[linus.luessing@c0d3.blue: Added commit message] +Signed-off-by: Linus Lüssing <linus.luessing@c0d3.blue> +Signed-off-by: Sven Eckelmann <sven@narfation.org> + +Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/eb60b63140af5ec01ea0916837c2816cad10d6c1 +--- + net/batman-adv/main.h | 2 +- + 1 file changed, 1 insertion(+), 1 deletion(-) + +diff --git a/net/batman-adv/main.h b/net/batman-adv/main.h +index a6cc8040a21dd24fb507683230fd66a9edb62458..5b7855560e8ad121c7b48da97807b6895be158fc 100644 +--- a/net/batman-adv/main.h ++++ b/net/batman-adv/main.h +@@ -168,7 +168,7 @@ enum batadv_uev_type { + /* Maximum number of fragments for one packet */ + #define BATADV_FRAG_MAX_FRAGMENTS 16 + /* Maxumim size of each fragment */ +-#define BATADV_FRAG_MAX_FRAG_SIZE 1400 ++#define BATADV_FRAG_MAX_FRAG_SIZE 1280 + /* Time to keep fragments while waiting for rest of the fragments */ + #define BATADV_FRAG_TIMEOUT 10000 + |