tc: cls_bpf: handle skip_sw and skip_hw flags

Add support for controling hardware offload using (now standard)
skip_sw and skip_hw flags in cls_bpf.

Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Simon Horman <simon.horman@netronome.com>

diff --git a/man/man8/tc-bpf.8 b/man/man8/tc-bpf.8
index c8d5c5f94da800cdb72c063742549c5c8d187e25..e371964d06ab9630945306f8fea27221b7232bab 100644 (file)
--- a/man/man8/tc-bpf.8
+++ b/man/man8/tc-bpf.8
@@ -14,6 +14,10 @@ CLS_NAME ] [
 UDS_FILE ] [
 .B verbose
 ] [
+.B skip_hw
+|
+.B skip_sw
+] [
 .B police
 POLICE_SPEC ] [
 .B action
@@ -137,6 +141,16 @@ if set, it will dump the eBPF verifier output, even if loading the eBPF
 program was successful. By default, only on error, the verifier log is
 being emitted to the user.
 
+.SS skip_hw | skip_sw
+hardware offload control flags. By default TC will try to offload
+filters to hardware if possible.
+.B skip_hw
+explicitly disables the attempt to offload.
+.B skip_sw
+forces the offload and disables running the eBPF program in the kernel.
+If hardware offload is not possible and this flag was set kernel will
+report an error and filter will not be installed at all.
+
 .SS police
 is an optional parameter for an eBPF/cBPF classifier that specifies a
 police in

diff --git a/tc/f_bpf.c b/tc/f_bpf.c
index 5c97c863d15aa2ceefef9eafc2a317ad3e159826..665bc6612eeb92891379c4134c46511760eb6205 100644 (file)
--- a/tc/f_bpf.c
+++ b/tc/f_bpf.c
@@ -37,8 +37,8 @@ static void explain(void)
        fprintf(stderr, "\n");
        fprintf(stderr, "eBPF use case:\n");
        fprintf(stderr, " object-file FILE [ section CLS_NAME ] [ export UDS_FILE ]");
-       fprintf(stderr, " [ verbose ] [ direct-action ]\n");
-       fprintf(stderr, " object-pinned FILE [ direct-action ]\n");
+       fprintf(stderr, " [ verbose ] [ direct-action ] [ skip_hw | skip_sw ]\n");
+       fprintf(stderr, " object-pinned FILE [ direct-action ] [ skip_hw | skip_sw ]\n");
        fprintf(stderr, "\n");
        fprintf(stderr, "Common remaining options:\n");
        fprintf(stderr, " [ action ACTION_SPEC ]\n");
@@ -66,6 +66,7 @@ static int bpf_parse_opt(struct filter_util *qu, char *handle,
 {
        const char *bpf_obj = NULL, *bpf_uds_name = NULL;
        struct tcmsg *t = NLMSG_DATA(n);
+       unsigned int bpf_gen_flags = 0;
        unsigned int bpf_flags = 0;
        bool seen_run = false;
        struct rtattr *tail;
@@ -107,6 +108,10 @@ opt_bpf:
                } else if (matches(*argv, "direct-action") == 0 ||
                           matches(*argv, "da") == 0) {
                        bpf_flags |= TCA_BPF_FLAG_ACT_DIRECT;
+               } else if (matches(*argv, "skip_hw") == 0) {
+                       bpf_gen_flags |= TCA_CLS_FLAGS_SKIP_HW;
+               } else if (matches(*argv, "skip_sw") == 0) {
+                       bpf_gen_flags |= TCA_CLS_FLAGS_SKIP_SW;
                } else if (matches(*argv, "action") == 0) {
                        NEXT_ARG();
                        if (parse_action(&argc, &argv, TCA_BPF_ACT, n)) {
@@ -136,6 +141,8 @@ opt_bpf:
                NEXT_ARG_FWD();
        }
 
+       if (bpf_gen_flags)
+               addattr32(n, MAX_MSG, TCA_BPF_FLAGS_GEN, bpf_gen_flags);
        if (bpf_obj && bpf_flags)
                addattr32(n, MAX_MSG, TCA_BPF_FLAGS, bpf_flags);
 
@@ -178,6 +185,16 @@ static int bpf_print_opt(struct filter_util *qu, FILE *f,
                        fprintf(f, "direct-action ");
        }
 
+       if (tb[TCA_BPF_FLAGS_GEN]) {
+               unsigned int flags =
+                       rta_getattr_u32(tb[TCA_BPF_FLAGS_GEN]);
+
+               if (flags & TCA_CLS_FLAGS_SKIP_HW)
+                       fprintf(f, "skip_hw ");
+               if (flags & TCA_CLS_FLAGS_SKIP_SW)
+                       fprintf(f, "skip_sw ");
+       }
+
        if (tb[TCA_BPF_OPS] && tb[TCA_BPF_OPS_LEN]) {
                bpf_print_ops(f, tb[TCA_BPF_OPS],
                              rta_getattr_u16(tb[TCA_BPF_OPS_LEN]));