| Message ID | 20231128023058.53546-1-qde@naccy.de (mailing list archive) |
|---|---|
| Headers | show |
| Series | ss: pretty-printing BPF socket-local storage | expand |
On Mon, 27 Nov 2023 18:30:55 -0800 Quentin Deslandes <qde@naccy.de> wrote: > BPF allows programs to store socket-specific data using > BPF_MAP_TYPE_SK_STORAGE maps. The data is attached to the socket itself, > and Martin added INET_DIAG_REQ_SK_BPF_STORAGES, so it can be fetched > using the INET_DIAG mechanism. > > Currently, ss doesn't request the socket-local data, this patch aims to > fix this. > > The first patch fixes a bug where the "Process" column would always be > printed on ss' output, even if --processes/-p is not used. > > Patch #2 requests the socket-local data for the requested map ID > (--bpf-map-id=) or all the maps (--bpf-maps). It then prints the map_id > in a dedicated column. > > Patch #3 uses libbpf and BTF to pretty print the map's content, like > `bpftool map dump` would do. > > While I think it makes sense for ss to provide the socket-local storage > content for the sockets, it's difficult to conciliate the column-based > output of ss and having readable socket-local data. Hence, the > socket-local data is printed in a readable fashion over multiple lines > under its socket statistics, independently of the column-based approach. > > Here is an example of ss' output with --bpf-maps: > [...] > ESTAB 2960280 0 [...] > map_id: 259 [ > (struct my_sk_storage) { > .field_hh = (char)127, > .<anon> = (union <anon>) { > .a = (int)0, > .b = (int)0, > }, > }, > ] > > Quentin Deslandes (3): > ss: prevent "Process" column from being printed unless requested > ss: add support for BPF socket-local storage > ss: pretty-print BPF socket-local storage > > misc/ss.c | 822 +++++++++++++++++++++++++++++++++++++++++++++++++++++- > 1 file changed, 818 insertions(+), 4 deletions(-) Useful, but ss is growing into a huge monolithic program and may need some refactoring. Also, this cries out for a json output format. Which ss doesn't have yet.
On 2023-11-28 23:43, Stephen Hemminger wrote: > On Mon, 27 Nov 2023 18:30:55 -0800 > Quentin Deslandes <qde@naccy.de> wrote: > >> BPF allows programs to store socket-specific data using >> BPF_MAP_TYPE_SK_STORAGE maps. The data is attached to the socket itself, >> and Martin added INET_DIAG_REQ_SK_BPF_STORAGES, so it can be fetched >> using the INET_DIAG mechanism. >> >> Currently, ss doesn't request the socket-local data, this patch aims to >> fix this. >> >> The first patch fixes a bug where the "Process" column would always be >> printed on ss' output, even if --processes/-p is not used. >> >> Patch #2 requests the socket-local data for the requested map ID >> (--bpf-map-id=) or all the maps (--bpf-maps). It then prints the map_id >> in a dedicated column. >> >> Patch #3 uses libbpf and BTF to pretty print the map's content, like >> `bpftool map dump` would do. >> >> While I think it makes sense for ss to provide the socket-local storage >> content for the sockets, it's difficult to conciliate the column-based >> output of ss and having readable socket-local data. Hence, the >> socket-local data is printed in a readable fashion over multiple lines >> under its socket statistics, independently of the column-based approach. >> >> Here is an example of ss' output with --bpf-maps: >> [...] >> ESTAB 2960280 0 [...] >> map_id: 259 [ >> (struct my_sk_storage) { >> .field_hh = (char)127, >> .<anon> = (union <anon>) { >> .a = (int)0, >> .b = (int)0, >> }, >> }, >> ] >> >> Quentin Deslandes (3): >> ss: prevent "Process" column from being printed unless requested >> ss: add support for BPF socket-local storage >> ss: pretty-print BPF socket-local storage >> >> misc/ss.c | 822 +++++++++++++++++++++++++++++++++++++++++++++++++++++- >> 1 file changed, 818 insertions(+), 4 deletions(-) > > > Useful, but ss is growing into a huge monolithic program and may need some > refactoring. Also, this cries out for a json output format. Which ss doesn't > have yet. I've submitted a v2 to fix Martin's comments and also improve the printing behavior. The updated revision reduces the number of lines added by 50%. Regarding the JSON output, is it specifically for socket-local storage, or more generally, for the whole tool? I agree with you anyway, but I would argue that it doesn't fit this series, although I can work on this as a next step.
On Fri, 8 Dec 2023 16:01:56 +0100 Quentin Deslandes <qde@naccy.de> wrote: > I've submitted a v2 to fix Martin's comments and also improve the printing > behavior. The updated revision reduces the number of lines added by 50%. Not sure about what best format for this is. > > Regarding the JSON output, is it specifically for socket-local storage, or > more generally, for the whole tool? I agree with you anyway, but I would argue > that it doesn't fit this series, although I can work on this as a next step. It is more for the whole tool in future.
BPF allows programs to store socket-specific data using BPF_MAP_TYPE_SK_STORAGE maps. The data is attached to the socket itself, and Martin added INET_DIAG_REQ_SK_BPF_STORAGES, so it can be fetched using the INET_DIAG mechanism. Currently, ss doesn't request the socket-local data, this patch aims to fix this. The first patch fixes a bug where the "Process" column would always be printed on ss' output, even if --processes/-p is not used. Patch #2 requests the socket-local data for the requested map ID (--bpf-map-id=) or all the maps (--bpf-maps). It then prints the map_id in a dedicated column. Patch #3 uses libbpf and BTF to pretty print the map's content, like `bpftool map dump` would do. While I think it makes sense for ss to provide the socket-local storage content for the sockets, it's difficult to conciliate the column-based output of ss and having readable socket-local data. Hence, the socket-local data is printed in a readable fashion over multiple lines under its socket statistics, independently of the column-based approach. Here is an example of ss' output with --bpf-maps: [...] ESTAB 2960280 0 [...] map_id: 259 [ (struct my_sk_storage) { .field_hh = (char)127, .<anon> = (union <anon>) { .a = (int)0, .b = (int)0, }, }, ] Quentin Deslandes (3): ss: prevent "Process" column from being printed unless requested ss: add support for BPF socket-local storage ss: pretty-print BPF socket-local storage misc/ss.c | 822 +++++++++++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 818 insertions(+), 4 deletions(-)