iw: Add support for showing Beacon IEs and TIM IE

An undocumented '-b' option can now be used with scan commands
to request the IEs from Beacon frames to be shown in addition to
the Probe Response IEs. TIM IE is parsed so that the DTIM period
is more easily available.

The '-b' option could be made to work with '-u' and get documented
if the command argument parsing were to be somewhat more flexible,
but that is a task for another change..

diff --git a/scan.c b/scan.c
index 308d4995edf0227d47fb671cd3a88025cff7ecc5..999aba46cbe6922321245d7ea0a895182742ffcf 100644 (file)
--- a/scan.c
+++ b/scan.c
@@ -33,6 +33,7 @@ static unsigned char ieee80211_oui[3] = { 0x00, 0x0f, 0xac };
 struct scan_params {
        bool unknown;
        enum print_ie_type type;
+       bool show_both_ie_sets;
 };
 
 static int handle_scan(struct nl80211_state *state,
@@ -484,6 +485,16 @@ static void print_capabilities(const uint8_t type, uint8_t len, const uint8_t *d
        printf("\n");
 }
 
+static void print_tim(const uint8_t type, uint8_t len, const uint8_t *data)
+{
+       printf(" DTIM Count %u DTIM Period %u Bitmap Control 0x%x "
+              "Bitmap[0] 0x%x",
+              data[0], data[1], data[2], data[3]);
+       if (len - 4)
+               printf(" (+ %u octet%s)", len - 4, len - 4 == 1 ? "" : "s");
+       printf("\n");
+}
+
 struct ie_print {
        const char *name;
        void (*print)(const uint8_t type, uint8_t len, const uint8_t *data);
@@ -527,7 +538,7 @@ static const struct ie_print ieprinters[] = {
        [0] = { "SSID", print_ssid, 0, 32, BIT(PRINT_SCAN) | BIT(PRINT_LINK), },
        [1] = { "Supported rates", print_supprates, 0, 255, BIT(PRINT_SCAN), },
        [3] = { "DS Parameter set", print_ds, 1, 1, BIT(PRINT_SCAN), },
-       [5] = PRINT_IGN,
+       [5] = { "TIM", print_tim, 4, 255, BIT(PRINT_SCAN), },
        [7] = { "Country", print_country, 3, 255, BIT(PRINT_SCAN), },
        [32] = { "Power constraint", print_powerconstraint, 1, 1, BIT(PRINT_SCAN), },
        [42] = { "ERP", print_erp, 1, 255, BIT(PRINT_SCAN), },
@@ -769,6 +780,7 @@ static int print_bss_handler(struct nl_msg *msg, void *arg)
                [NL80211_BSS_SIGNAL_UNSPEC] = { .type = NLA_U8 },
                [NL80211_BSS_STATUS] = { .type = NLA_U32 },
                [NL80211_BSS_SEEN_MS_AGO] = { .type = NLA_U32 },
+               [NL80211_BSS_BEACON_IES] = { },
        };
        struct scan_params *params = arg;
 
@@ -864,10 +876,20 @@ static int print_bss_handler(struct nl_msg *msg, void *arg)
                int age = nla_get_u32(bss[NL80211_BSS_SEEN_MS_AGO]);
                printf("\tlast seen: %d ms ago\n", age);
        }
-       if (bss[NL80211_BSS_INFORMATION_ELEMENTS])
+       if (bss[NL80211_BSS_INFORMATION_ELEMENTS]) {
+               if (bss[NL80211_BSS_BEACON_IES])
+                       printf("\tInformation elements from Probe Response "
+                              "frame:\n");
                print_ies(nla_data(bss[NL80211_BSS_INFORMATION_ELEMENTS]),
                          nla_len(bss[NL80211_BSS_INFORMATION_ELEMENTS]),
                          params->unknown, params->type);
+       }
+       if (bss[NL80211_BSS_BEACON_IES]) {
+               printf("\tInformation elements from Beacon frame:\n");
+               print_ies(nla_data(bss[NL80211_BSS_BEACON_IES]),
+                         nla_len(bss[NL80211_BSS_BEACON_IES]),
+                         params->unknown, params->type);
+       }
 
        return NL_SKIP;
 }
@@ -885,6 +907,8 @@ static int handle_scan_dump(struct nl80211_state *state,
        scan_params.unknown = false;
        if (argc == 1 && !strcmp(argv[0], "-u"))
                scan_params.unknown = true;
+       else if (argc == 1 && !strcmp(argv[0], "-b"))
+               scan_params.show_both_ie_sets = true;
 
        scan_params.type = PRINT_SCAN;
 
@@ -914,6 +938,9 @@ static int handle_scan_combined(struct nl80211_state *state,
        if (argc >= 3 && !strcmp(argv[2], "-u")) {
                dump_argc = 4;
                dump_argv[3] = "-u";
+       } else if (argc >= 3 && !strcmp(argv[2], "-b")) {
+               dump_argc = 4;
+               dump_argv[3] = "-b";
        } else
                dump_argc = 3;