bpf: properly output json for xdp

After merging net-next branch into master, Stephen asked
to fix up json dump for XDP. Thus, rework the json dump a
bit, such that 'ip -json l' looks as below.

  [{
        "ifindex": 1,
        "ifname": "lo",
        "flags": ["LOOPBACK","UP","LOWER_UP"],
        "mtu": 65536,
        "xdp": {
            "mode": 2,
            "prog": {
                "id": 5,
                "tag": "e1e9d0ec0f55d638",
                "jited": 1
            }
        },
        "qdisc": "noqueue",
        "operstate": "UNKNOWN",
        "linkmode": "DEFAULT",
        "group": "default",
        "txqlen": 1000,
        "link_type": "loopback",
        "address": "00:00:00:00:00:00",
        "broadcast": "00:00:00:00:00:00"
    },[...]
  ]

Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

diff --git a/ip/iplink_xdp.c b/ip/iplink_xdp.c
index 71f77982580e172349ea6aa6abf11ecabc82f2ec..2d2953aa47a83fa9133d2668f6d910502cfd8a8d 100644 (file)
--- a/ip/iplink_xdp.c
+++ b/ip/iplink_xdp.c
@@ -14,9 +14,9 @@
 
 #include <linux/bpf.h>
 
+#include "json_print.h"
 #include "xdp.h"
 #include "bpf_util.h"
-#include "ip_common.h"
 
 extern int force;
 
@@ -82,6 +82,22 @@ int xdp_parse(int *argc, char ***argv, struct iplink_req *req, bool generic,
        return 0;
 }
 
+static void xdp_dump_json(struct rtattr *tb[IFLA_XDP_MAX + 1])
+{
+       __u32 prog_id = 0;
+       __u8 mode;
+
+       mode = rta_getattr_u8(tb[IFLA_XDP_ATTACHED]);
+       if (tb[IFLA_XDP_PROG_ID])
+               prog_id = rta_getattr_u32(tb[IFLA_XDP_PROG_ID]);
+
+       open_json_object("xdp");
+       print_uint(PRINT_JSON, "mode", NULL, mode);
+       if (prog_id)
+               bpf_dump_prog_info(NULL, prog_id);
+       close_json_object();
+}
+
 void xdp_dump(FILE *fp, struct rtattr *xdp, bool link, bool details)
 {
        struct rtattr *tb[IFLA_XDP_MAX + 1];
@@ -94,34 +110,32 @@ void xdp_dump(FILE *fp, struct rtattr *xdp, bool link, bool details)
                return;
 
        mode = rta_getattr_u8(tb[IFLA_XDP_ATTACHED]);
-       if (is_json_context()) {
-               print_uint(PRINT_JSON, "attached", NULL, mode);
-       } else {
-               if (mode == XDP_ATTACHED_NONE)
-                       return;
-               else if (details && link)
-                       fprintf(fp, "%s    prog/xdp", _SL_);
-               else if (mode == XDP_ATTACHED_DRV)
-                       fprintf(fp, "xdp");
-               else if (mode == XDP_ATTACHED_SKB)
-                       fprintf(fp, "xdpgeneric");
-               else if (mode == XDP_ATTACHED_HW)
-                       fprintf(fp, "xdpoffload");
-               else
-                       fprintf(fp, "xdp[%u]", mode);
-
-               if (tb[IFLA_XDP_PROG_ID])
-                       prog_id = rta_getattr_u32(tb[IFLA_XDP_PROG_ID]);
-               if (!details) {
-                       if (prog_id && !link)
-                               fprintf(fp, "/id:%u", prog_id);
-                       fprintf(fp, " ");
-                       return;
-               }
-
-               if (prog_id) {
-                       fprintf(fp, " ");
-                       bpf_dump_prog_info(fp, prog_id);
-               }
+       if (mode == XDP_ATTACHED_NONE)
+               return;
+       else if (is_json_context())
+               return details ? (void)0 : xdp_dump_json(tb);
+       else if (details && link)
+               fprintf(fp, "%s    prog/xdp", _SL_);
+       else if (mode == XDP_ATTACHED_DRV)
+               fprintf(fp, "xdp");
+       else if (mode == XDP_ATTACHED_SKB)
+               fprintf(fp, "xdpgeneric");
+       else if (mode == XDP_ATTACHED_HW)
+               fprintf(fp, "xdpoffload");
+       else
+               fprintf(fp, "xdp[%u]", mode);
+
+       if (tb[IFLA_XDP_PROG_ID])
+               prog_id = rta_getattr_u32(tb[IFLA_XDP_PROG_ID]);
+       if (!details) {
+               if (prog_id && !link)
+                       fprintf(fp, "/id:%u", prog_id);
+               fprintf(fp, " ");
+               return;
+       }
+
+       if (prog_id) {
+               fprintf(fp, " ");
+               bpf_dump_prog_info(fp, prog_id);
        }
 }

diff --git a/lib/bpf.c b/lib/bpf.c
index cfa1f79af06d86e0459e66c7a90ba37dc3c87d8c..10ea23a471ef2341724d6b51ec95bc6c758e07fd 100644 (file)
--- a/lib/bpf.c
+++ b/lib/bpf.c
@@ -40,6 +40,7 @@
 #include <arpa/inet.h>
 
 #include "utils.h"
+#include "json_print.h"
 
 #include "bpf_util.h"
 #include "bpf_elf.h"
@@ -186,23 +187,29 @@ int bpf_dump_prog_info(FILE *f, uint32_t id)
        int fd, ret, dump_ok = 0;
        SPRINT_BUF(tmp);
 
-       fprintf(f, "id %u ", id);
+       open_json_object("prog");
+       print_uint(PRINT_ANY, "id", "id %u ", id);
 
        fd = bpf_prog_fd_by_id(id);
        if (fd < 0)
-               return dump_ok;
+               goto out;
 
        ret = bpf_prog_info_by_fd(fd, &info, &len);
        if (!ret && len) {
-               fprintf(f, "tag %s ",
-                       hexstring_n2a(info.tag, sizeof(info.tag),
-                                     tmp, sizeof(tmp)));
-               if (info.jited_prog_len)
+               int jited = !!info.jited_prog_len;
+
+               print_string(PRINT_ANY, "tag", "tag %s ",
+                            hexstring_n2a(info.tag, sizeof(info.tag),
+                                          tmp, sizeof(tmp)));
+               print_uint(PRINT_JSON, "jited", NULL, jited);
+               if (jited && !is_json_context())
                        fprintf(f, "jited ");
                dump_ok = 1;
        }
 
        close(fd);
+out:
+       close_json_object();
        return dump_ok;
 }