| Message ID | 158472337077.296548.4666186362987360141.stgit@toke.dk |
|---|---|
| State | Changes Requested |
| Delegated to: | BPF Maintainers |
| Headers | show |
| Series | XDP: Support atomic replacement of XDP interface attachments | expand |
On Fri, Mar 20, 2020 at 9:57 AM Toke Høiland-Jørgensen <toke@redhat.com> wrote: > > From: Toke Høiland-Jørgensen <toke@redhat.com> > > This adds a new function to set the XDP fd while specifying the old fd to > replace, using the newly added IFLA_XDP_EXPECTED_FD netlink parameter. > > Signed-off-by: Toke Høiland-Jørgensen <toke@redhat.com> > --- > tools/lib/bpf/libbpf.h | 2 ++ > tools/lib/bpf/libbpf.map | 1 + > tools/lib/bpf/netlink.c | 22 +++++++++++++++++++++- > 3 files changed, 24 insertions(+), 1 deletion(-) > > diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h > index d38d7a629417..b5ca4f741e28 100644 > --- a/tools/lib/bpf/libbpf.h > +++ b/tools/lib/bpf/libbpf.h > @@ -445,6 +445,8 @@ struct xdp_link_info { > }; > > LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags); > +LIBBPF_API int bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, > + __u32 flags); If we end up doing it in XDP-specific way, I'd argue for using OPTS to specify optional expected FD. That will allow to extend this API further without adding many small variations of the same API. > LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags); > LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info, > size_t info_size, __u32 flags); > diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map > index 5129283c0284..154f1d94fa63 100644 > --- a/tools/lib/bpf/libbpf.map > +++ b/tools/lib/bpf/libbpf.map > @@ -244,4 +244,5 @@ LIBBPF_0.0.8 { > bpf_link__pin_path; > bpf_link__unpin; > bpf_program__set_attach_target; > + bpf_set_link_xdp_fd_replace; > } LIBBPF_0.0.7; > diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c > index 431bd25c6cdb..39bd0ead1546 100644 > --- a/tools/lib/bpf/netlink.c > +++ b/tools/lib/bpf/netlink.c > @@ -132,7 +132,8 @@ static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq, > return ret; > } > > -int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) > +static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, > + __u32 flags) > { > int sock, seq = 0, ret; > struct nlattr *nla, *nla_xdp; > @@ -178,6 +179,14 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) > nla->nla_len += nla_xdp->nla_len; > } > > + if (flags & XDP_FLAGS_EXPECT_FD) { > + nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); > + nla_xdp->nla_type = IFLA_XDP_EXPECTED_FD; > + nla_xdp->nla_len = NLA_HDRLEN + sizeof(int); > + memcpy((char *)nla_xdp + NLA_HDRLEN, &old_fd, sizeof(old_fd)); > + nla->nla_len += nla_xdp->nla_len; > + } > + > req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len); > > if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) { > @@ -191,6 +200,17 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) > return ret; > } > > +int bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, __u32 flags) > +{ > + return __bpf_set_link_xdp_fd_replace(ifindex, fd, old_fd, > + flags | XDP_FLAGS_EXPECT_FD); > +} > + > +int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) > +{ > + return __bpf_set_link_xdp_fd_replace(ifindex, fd, -1, flags); > +} > + > static int __dump_link_nlmsg(struct nlmsghdr *nlh, > libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie) > { >
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index d38d7a629417..b5ca4f741e28 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -445,6 +445,8 @@ struct xdp_link_info { }; LIBBPF_API int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags); +LIBBPF_API int bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, + __u32 flags); LIBBPF_API int bpf_get_link_xdp_id(int ifindex, __u32 *prog_id, __u32 flags); LIBBPF_API int bpf_get_link_xdp_info(int ifindex, struct xdp_link_info *info, size_t info_size, __u32 flags); diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map index 5129283c0284..154f1d94fa63 100644 --- a/tools/lib/bpf/libbpf.map +++ b/tools/lib/bpf/libbpf.map @@ -244,4 +244,5 @@ LIBBPF_0.0.8 { bpf_link__pin_path; bpf_link__unpin; bpf_program__set_attach_target; + bpf_set_link_xdp_fd_replace; } LIBBPF_0.0.7; diff --git a/tools/lib/bpf/netlink.c b/tools/lib/bpf/netlink.c index 431bd25c6cdb..39bd0ead1546 100644 --- a/tools/lib/bpf/netlink.c +++ b/tools/lib/bpf/netlink.c @@ -132,7 +132,8 @@ static int bpf_netlink_recv(int sock, __u32 nl_pid, int seq, return ret; } -int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) +static int __bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, + __u32 flags) { int sock, seq = 0, ret; struct nlattr *nla, *nla_xdp; @@ -178,6 +179,14 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) nla->nla_len += nla_xdp->nla_len; } + if (flags & XDP_FLAGS_EXPECT_FD) { + nla_xdp = (struct nlattr *)((char *)nla + nla->nla_len); + nla_xdp->nla_type = IFLA_XDP_EXPECTED_FD; + nla_xdp->nla_len = NLA_HDRLEN + sizeof(int); + memcpy((char *)nla_xdp + NLA_HDRLEN, &old_fd, sizeof(old_fd)); + nla->nla_len += nla_xdp->nla_len; + } + req.nh.nlmsg_len += NLA_ALIGN(nla->nla_len); if (send(sock, &req, req.nh.nlmsg_len, 0) < 0) { @@ -191,6 +200,17 @@ int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) return ret; } +int bpf_set_link_xdp_fd_replace(int ifindex, int fd, int old_fd, __u32 flags) +{ + return __bpf_set_link_xdp_fd_replace(ifindex, fd, old_fd, + flags | XDP_FLAGS_EXPECT_FD); +} + +int bpf_set_link_xdp_fd(int ifindex, int fd, __u32 flags) +{ + return __bpf_set_link_xdp_fd_replace(ifindex, fd, -1, flags); +} + static int __dump_link_nlmsg(struct nlmsghdr *nlh, libbpf_dump_nlmsg_t dump_link_nlmsg, void *cookie) {