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https://github.com/AuxXxilium/linux_dsm_epyc7002.git
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"Post-hooks" are hooks that are called right before returning from sys_bind. At this time IP and port are already allocated and no further changes to `struct sock` can happen before returning from sys_bind but BPF program has a chance to inspect the socket and change sys_bind result. Specifically it can e.g. inspect what port was allocated and if it doesn't satisfy some policy, BPF program can force sys_bind to fail and return EPERM to user. Another example of usage is recording the IP:port pair to some map to use it in later calls to sys_connect. E.g. if some TCP server inside cgroup was bound to some IP:port_n, it can be recorded to a map. And later when some TCP client inside same cgroup is trying to connect to 127.0.0.1:port_n, BPF hook for sys_connect can override the destination and connect application to IP:port_n instead of 127.0.0.1:port_n. That helps forcing all applications inside a cgroup to use desired IP and not break those applications if they e.g. use localhost to communicate between each other. == Implementation details == Post-hooks are implemented as two new attach types `BPF_CGROUP_INET4_POST_BIND` and `BPF_CGROUP_INET6_POST_BIND` for existing prog type `BPF_PROG_TYPE_CGROUP_SOCK`. Separate attach types for IPv4 and IPv6 are introduced to avoid access to IPv6 field in `struct sock` from `inet_bind()` and to IPv4 field from `inet6_bind()` since those fields might not make sense in such cases. Signed-off-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> |
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.. | ||
datagram.c | ||
dev_addr_lists.c | ||
dev_ioctl.c | ||
dev.c | ||
devlink.c | ||
drop_monitor.c | ||
dst_cache.c | ||
dst.c | ||
ethtool.c | ||
fib_notifier.c | ||
fib_rules.c | ||
filter.c | ||
flow_dissector.c | ||
gen_estimator.c | ||
gen_stats.c | ||
gro_cells.c | ||
hwbm.c | ||
link_watch.c | ||
lwt_bpf.c | ||
lwtunnel.c | ||
Makefile | ||
neighbour.c | ||
net_namespace.c | ||
net-procfs.c | ||
net-sysfs.c | ||
net-sysfs.h | ||
net-traces.c | ||
netclassid_cgroup.c | ||
netevent.c | ||
netpoll.c | ||
netprio_cgroup.c | ||
pktgen.c | ||
ptp_classifier.c | ||
request_sock.c | ||
rtnetlink.c | ||
scm.c | ||
secure_seq.c | ||
skbuff.c | ||
sock_diag.c | ||
sock_reuseport.c | ||
sock.c | ||
stream.c | ||
sysctl_net_core.c | ||
timestamping.c | ||
tso.c | ||
utils.c | ||
xdp.c |