kernel/linux.git/net/tipc/bcast.c, branch v6.12.80

net: tipc: avoid possible garbage value

2024-09-14T03:03:43+00:00

Clang static checker (scan-build) warning: net/tipc/bcast.c:305:4: The expression is an uninitialized value. The computed value will also be garbage [core.uninitialized.Assign] 305 | (*cong_link_cnt)++; | ^~~~~~~~~~~~~~~~~~ tipc_rcast_xmit() will increase cong_link_cnt's value, but cong_link_cnt is uninitialized. Although it won't really cause a problem, it's better to fix it. Fixes: dca4a17d24ee ("tipc: fix potential hanging after b/rcast changing") Signed-off-by: Su Hui Reviewed-by: Justin Stitt Link: https://patch.msgid.link/20240912110119.2025503-1-suhui@nfschina.com Signed-off-by: Jakub Kicinski

net: tipc: fix FB_MTU eat two pages

2021-06-28T20:31:57+00:00

FB_MTU is used in 'tipc_msg_build()' to alloc smaller skb when memory allocation fails, which can avoid unnecessary sending failures. The value of FB_MTU now is 3744, and the data size will be: (3744 + SKB_DATA_ALIGN(sizeof(struct skb_shared_info)) + \ SKB_DATA_ALIGN(BUF_HEADROOM + BUF_TAILROOM + 3)) which is larger than one page(4096), and two pages will be allocated. To avoid it, replace '3744' with a calculation: (PAGE_SIZE - SKB_DATA_ALIGN(BUF_OVERHEAD) - \ SKB_DATA_ALIGN(sizeof(struct skb_shared_info))) What's more, alloc_skb_fclone() will call SKB_DATA_ALIGN for data size, and it's not necessary to make alignment for buf_size in tipc_buf_acquire(). So, just remove it. Fixes: 4c94cc2d3d57 ("tipc: fall back to smaller MTU if allocation of local send skb fails") Signed-off-by: Menglong Dong Acked-by: Jon Maloy Signed-off-by: David S. Miller

tipc: fix incorrect setting window for bcast link

2020-10-16T21:09:12+00:00

In commit 16ad3f4022bb ("tipc: introduce variable window congestion control"), we applied the algorithm to select window size from minimum window to the configured maximum window for unicast link, and, besides we chose to keep the window size for broadcast link unchanged and equal (i.e fix window 50) However, when setting maximum window variable via command, the window variable was re-initialized to unexpect value (i.e 32). We fix this by updating the fix window for broadcast as we stated. Fixes: 16ad3f4022bb ("tipc: introduce variable window congestion control") Acked-by: Jon Maloy Signed-off-by: Hoang Huu Le Signed-off-by: Jakub Kicinski

tipc: re-configure queue limit for broadcast link

2020-10-16T21:09:12+00:00

The queue limit of the broadcast link is being calculated base on initial MTU. However, when MTU value changed (e.g manual changing MTU on NIC device, MTU negotiation etc.,) we do not re-calculate queue limit. This gives throughput does not reflect with the change. So fix it by calling the function to re-calculate queue limit of the broadcast link. Acked-by: Jon Maloy Signed-off-by: Hoang Huu Le Signed-off-by: Jakub Kicinski

tipc: update a binding service via broadcast

2020-06-17T15:53:34+00:00

Currently, updating binding table (add service binding to name table/withdraw a service binding) is being sent over replicast. However, if we are scaling up clusters to > 100 nodes/containers this method is less affection because of looping through nodes in a cluster one by one. It is worth to use broadcast to update a binding service. This way, the binding table can be updated on all peer nodes in one shot. Broadcast is used when all peer nodes, as indicated by a new capability flag TIPC_NAMED_BCAST, support reception of this message type. Four problems need to be considered when introducing this feature. 1) When establishing a link to a new peer node we still update this by a unicast 'bulk' update. This may lead to race conditions, where a later broadcast publication/withdrawal bypass the 'bulk', resulting in disordered publications, or even that a withdrawal may arrive before the corresponding publication. We solve this by adding an 'is_last_bulk' bit in the last bulk messages so that it can be distinguished from all other messages. Only when this message has arrived do we open up for reception of broadcast publications/withdrawals. 2) When a first legacy node is added to the cluster all distribution will switch over to use the legacy 'replicast' method, while the opposite happens when the last legacy node leaves the cluster. This entails another risk of message disordering that has to be handled. We solve this by adding a sequence number to the broadcast/replicast messages, so that disordering can be discovered and corrected. Note however that we don't need to consider potential message loss or duplication at this protocol level. 3) Bulk messages don't contain any sequence numbers, and will always arrive in order. Hence we must exempt those from the sequence number control and deliver them unconditionally. We solve this by adding a new 'is_bulk' bit in those messages so that they can be recognized. 4) Legacy messages, which don't contain any new bits or sequence numbers, but neither can arrive out of order, also need to be exempt from the initial synchronization and sequence number check, and delivered unconditionally. Therefore, we add another 'is_not_legacy' bit to all new messages so that those can be distinguished from legacy messages and the latter delivered directly. v1->v2: - fix warning issue reported by kbuild test robot - add santiy check to drop the publication message with a sequence number that is lower than the agreed synch point Signed-off-by: kernel test robot Signed-off-by: Hoang Huu Le Acked-by: Jon Maloy Signed-off-by: David S. Miller

tipc: add support for broadcast rcv stats dumping

2020-05-26T22:16:52+00:00

This commit enables dumping the statistics of a broadcast-receiver link like the traditional 'broadcast-link' one (which is for broadcast- sender). The link dumping can be triggered via netlink (e.g. the iproute2/tipc tool) by the link flag - 'TIPC_NLA_LINK_BROADCAST' as the indicator. The name of a broadcast-receiver link of a specific peer will be in the format: 'broadcast-link:'. For example: Link Window:50 packets RX packets:7841 fragments:2408/440 bundles:0/0 TX packets:0 fragments:0/0 bundles:0/0 RX naks:0 defs:124 dups:0 TX naks:21 acks:0 retrans:0 Congestion link:0 Send queue max:0 avg:0 In addition, the broadcast-receiver link statistics can be reset in the usual way via netlink by specifying that link name in command. Note: the 'tipc_link_name_ext()' is removed because the link name can now be retrieved simply via the 'l->name'. Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: enable broadcast retrans via unicast

2020-05-26T22:16:52+00:00

In some environment, broadcast traffic is suppressed at high rate (i.e. a kind of bandwidth limit setting). When it is applied, TIPC broadcast can still run successfully. However, when it comes to a high load, some packets will be dropped first and TIPC tries to retransmit them but the packet retransmission is intentionally broadcast too, so making things worse and not helpful at all. This commit enables the broadcast retransmission via unicast which only retransmits packets to the specific peer that has really reported a gap i.e. not broadcasting to all nodes in the cluster, so will prevent from being suppressed, and also reduce some overheads on the other peers due to duplicates, finally improve the overall TIPC broadcast performance. Note: the functionality can be turned on/off via the sysctl file: echo 1 > /proc/sys/net/tipc/bc_retruni echo 0 > /proc/sys/net/tipc/bc_retruni Default is '0', i.e. the broadcast retransmission still works as usual. Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

tipc: introduce Gap ACK blocks for broadcast link

2020-05-26T22:16:52+00:00

As achieved through commit 9195948fbf34 ("tipc: improve TIPC throughput by Gap ACK blocks"), we apply the same mechanism for the broadcast link as well. The 'Gap ACK blocks' data field in a 'PROTOCOL/STATE_MSG' will consist of two parts built for both the broadcast and unicast types: 31 16 15 0 +-------------+-------------+-------------+-------------+ | bgack_cnt | ugack_cnt | len | +-------------+-------------+-------------+-------------+ - | gap | ack | | +-------------+-------------+-------------+-------------+ > bc gacks : : : | +-------------+-------------+-------------+-------------+ - | gap | ack | | +-------------+-------------+-------------+-------------+ > uc gacks : : : | +-------------+-------------+-------------+-------------+ - which is "automatically" backward-compatible. We also increase the max number of Gap ACK blocks to 128, allowing upto 64 blocks per type (total buffer size = 516 bytes). Besides, the 'tipc_link_advance_transmq()' function is refactored which is applicable for both the unicast and broadcast cases now, so some old functions can be removed and the code is optimized. With the patch, TIPC broadcast is more robust regardless of packet loss or disorder, latency, ... in the underlying network. Its performance is boost up significantly. For example, experiment with a 5% packet loss rate results: $ time tipc-pipe --mc --rdm --data_size 123 --data_num 1500000 real 0m 42.46s user 0m 1.16s sys 0m 17.67s Without the patch: $ time tipc-pipe --mc --rdm --data_size 123 --data_num 1500000 real 8m 27.94s user 0m 0.55s sys 0m 2.38s Acked-by: Ying Xue Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net

2019-12-22T23:15:05+00:00

Mere overlapping changes in the conflicts here. Signed-off-by: David S. Miller

tipc: fix potential hanging after b/rcast changing

2019-12-11T01:45:04+00:00

In commit c55c8edafa91 ("tipc: smooth change between replicast and broadcast"), we allow instant switching between replicast and broadcast by sending a dummy 'SYN' packet on the last used link to synchronize packets on the links. The 'SYN' message is an object of link congestion also, so if that happens, a 'SOCK_WAKEUP' will be scheduled to be sent back to the socket... However, in that commit, we simply use the same socket 'cong_link_cnt' counter for both the 'SYN' & normal payload message sending. Therefore, if both the replicast & broadcast links are congested, the counter will be not updated correctly but overwritten by the latter congestion. Later on, when the 'SOCK_WAKEUP' messages are processed, the counter is reduced one by one and eventually overflowed. Consequently, further activities on the socket will only wait for the false congestion signal to disappear but never been met. Because sending the 'SYN' message is vital for the mechanism, it should be done anyway. This commit fixes the issue by marking the message with an error code e.g. 'TIPC_ERR_NO_PORT', so its sending should not face a link congestion, there is no need to touch the socket 'cong_link_cnt' either. In addition, in the event of any error (e.g. -ENOBUFS), we will purge the entire payload message queue and make a return immediately. Fixes: c55c8edafa91 ("tipc: smooth change between replicast and broadcast") Acked-by: Jon Maloy Signed-off-by: Tuong Lien Signed-off-by: David S. Miller