/* \summary: MACsec printer */
-#ifdef HAVE_CONFIG_H
-#include "config.h"
-#endif
+#include <config.h>
-#include <netdissect-stdinc.h>
-
-#include <string.h>
+#include "netdissect-stdinc.h"
#include "netdissect.h"
#include "addrtoname.h"
-#include "ethertype.h"
#include "extract.h"
-static const char tstr[] = "[|MACsec]";
-
#define MACSEC_DEFAULT_ICV_LEN 16
/* Header format (SecTAG), following an Ethernet header
#define MACSEC_TCI_CONFID (MACSEC_TCI_E | MACSEC_TCI_C)
#define MACSEC_SL_MASK 0x3F /* short length */
-#define MACSEC_SECTAG_LEN_NOSCI 6
-#define MACSEC_SECTAG_LEN_SCI 14
-static int
-ieee8021ae_sectag_len(netdissect_options *ndo, const struct macsec_sectag *sectag)
-{
- return (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC) ?
- MACSEC_SECTAG_LEN_SCI :
- MACSEC_SECTAG_LEN_NOSCI;
-}
-
-static int macsec_check_length(netdissect_options *ndo, cconst struct macsec_sectag *sectag, u_int length, u_int caplen)
-{
- u_int len;
-
- /* we need the full MACsec header in the capture */
- if (caplen < (MACSEC_SECTAG_LEN_NOSCI + 2))
- return 0;
-
- len = ieee8021ae_sectag_len(ndo, sectag);
- if (caplen < (len + 2))
- return 0;
-
- if ((GET_U_1(sectag->short_length) & MACSEC_SL_MASK) != 0) {
- /* original packet must have exact length */
- u_int exact = ETHER_HDRLEN + len + 2 + (GET_U_1(sectag->short_length) & MACSEC_SL_MASK);
- return exact == length;
- } else {
- /* original packet must not be short */
- u_int minlen = ETHER_HDRLEN + len + 2 + 48;
- return length >= minlen;
- }
-
- return 1;
-}
+#define MACSEC_SECTAG_LEN_NOSCI 6 /* length of MACsec header without SCI */
+#define MACSEC_SECTAG_LEN_SCI 14 /* length of MACsec header with SCI */
#define SCI_FMT "%016" PRIx64
{ 0, NULL }
};
+static void
+macsec_print_header(netdissect_options *ndo,
+ const struct macsec_sectag *sectag,
+ u_int short_length)
+{
+ ND_PRINT("an %u, pn %u, flags %s",
+ GET_U_1(sectag->tci_an) & MACSEC_AN_MASK,
+ GET_BE_U_4(sectag->packet_number),
+ bittok2str_nosep(macsec_flag_values, "none",
+ GET_U_1(sectag->tci_an) & MACSEC_TCI_FLAGS));
+
+ if (short_length != 0)
+ ND_PRINT(", sl %u", short_length);
+
+ if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC)
+ ND_PRINT(", sci " SCI_FMT, GET_BE_U_8(sectag->secure_channel_id));
+
+ ND_PRINT(", ");
+}
+
/* returns < 0 iff the packet can be decoded completely */
-int macsec_print(netdissect_options *ndo, const u_char **bp,
- u_int *lengthp, u_int *caplenp, u_int *hdrlenp,
- u_short *length_type)
+int
+macsec_print(netdissect_options *ndo, const u_char **bp,
+ u_int *lengthp, u_int *caplenp, u_int *hdrlenp,
+ const struct lladdr_info *src, const struct lladdr_info *dst)
{
+ const char *save_protocol;
const u_char *p = *bp;
u_int length = *lengthp;
u_int caplen = *caplenp;
u_int hdrlen = *hdrlenp;
const struct macsec_sectag *sectag = (const struct macsec_sectag *)p;
- u_int len;
+ u_int sectag_len;
+ u_int short_length;
+
+ save_protocol = ndo->ndo_protocol;
+ ndo->ndo_protocol = "macsec";
- if (!macsec_check_length(sectag, length, caplen)) {
- ND_PRINT(tstr);
+ /* we need the full MACsec header in the capture */
+ if (caplen < MACSEC_SECTAG_LEN_NOSCI) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
return hdrlen + caplen;
}
-
- if (sectag->unused || sectag->tci_an & MACSEC_TCI_VERSION) {
- ND_PRINT("%s", istr);
+ if (length < MACSEC_SECTAG_LEN_NOSCI) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
return hdrlen + caplen;
}
- if (ndo->ndo_eflag) {
- char buf[128];
- int n = snprintf(buf, sizeof(buf), "an %u, pn %u, flags %s",
- GET_U_1(sectag->tci_an) & MACSEC_AN_MASK,
- GET_BE_U_4(sectag->packet_number),
- bittok2str_nosep(macsec_flag_values, "none",
- GET_U_1(sectag->tci_an) & MACSEC_TCI_FLAGS));
- if (n < 0)
+ if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC) {
+ sectag_len = MACSEC_SECTAG_LEN_SCI;
+ if (caplen < MACSEC_SECTAG_LEN_SCI) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
return hdrlen + caplen;
-
-
- if ((GET_U_1(sectag->short_length) & MACSEC_SL_MASK) != 0 {
- int r = snprintf(buf + n, sizeof(buf) - n, ", sl %u",
- GET_U_1(sectag->short_length) & MACSEC_SL_MASK);
- if (r < 0)
- return hdrlen + caplen;
- n += r;
}
-
- if (GET_U_1(sectag->tci_an) & MACSEC_TCI_SC) {
- uint64_t sci;
- int r;
- sci = GET_BE_U_8(sectag->secure_channel_id);
- r = snprintf(buf + n, sizeof(buf) - n, ", sci " SCI_FMT, sci);
- if (r < 0)
- return hdrlen + caplen;
- n += r;
+ if (length < MACSEC_SECTAG_LEN_SCI) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
+ return hdrlen + caplen;
}
+ } else
+ sectag_len = MACSEC_SECTAG_LEN_NOSCI;
- ND_PRINT("%s, ", buf);
+ if ((GET_U_1(sectag->short_length) & ~MACSEC_SL_MASK) != 0 ||
+ GET_U_1(sectag->tci_an) & MACSEC_TCI_VERSION) {
+ nd_print_invalid(ndo);
+ ndo->ndo_protocol = save_protocol;
+ return hdrlen + caplen;
}
- len = ieee8021ae_sectag_len(ndo, sectag);
- *length_type = GET_BE_U_2(*bp + len);
- if (ndo->ndo_eflag && *length_type > ETHERMTU && !(GET_U_1(sectag->tci_an) & MACSEC_TCI_E))
- ND_PRINT("ethertype %s, ", tok2str(ethertype_values,"0x%04x", *length_type));
+ short_length = GET_U_1(sectag->short_length) & MACSEC_SL_MASK;
+ if (ndo->ndo_eflag)
+ macsec_print_header(ndo, sectag, short_length);
+
+ /* Skip the MACsec header. */
+ *bp += sectag_len;
+ *hdrlenp += sectag_len;
+
+ /* Remove it from the lengths, as it's been processed. */
+ *lengthp -= sectag_len;
+ *caplenp -= sectag_len;
if ((GET_U_1(sectag->tci_an) & MACSEC_TCI_CONFID)) {
- *bp += len;
- *hdrlenp += len;
+ /*
+ * The payload is encrypted. Print link-layer
+ * information, if it hasn't already been printed.
+ */
+ if (!ndo->ndo_eflag) {
+ /*
+ * Nobody printed the link-layer addresses,
+ * so print them, if we have any.
+ */
+ if (src != NULL && dst != NULL) {
+ ND_PRINT("%s > %s ",
+ (src->addr_string)(ndo, src->addr),
+ (dst->addr_string)(ndo, dst->addr));
+ }
+
+ ND_PRINT("802.1AE MACsec, ");
+
+ /*
+ * Print the MACsec header.
+ */
+ macsec_print_header(ndo, sectag, short_length);
+ }
- *lengthp -= len;
- *caplenp -= len;
+ /*
+ * Tell our caller it can't be dissected.
+ */
+ ndo->ndo_protocol = save_protocol;
return 0;
- } else {
- len += 2;
- *bp += len;
- *hdrlenp += len;
-
- len += MACSEC_DEFAULT_ICV_LEN;
- *lengthp -= len;
- *caplenp -= len;
- return -1;
}
+
+ /*
+ * The payload isn't encrypted; remove the
+ * ICV length from the lengths, so our caller
+ * doesn't treat it as payload.
+ */
+ if (*lengthp < MACSEC_DEFAULT_ICV_LEN) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
+ return hdrlen + caplen;
+ }
+ if (*caplenp < MACSEC_DEFAULT_ICV_LEN) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
+ return hdrlen + caplen;
+ }
+ *lengthp -= MACSEC_DEFAULT_ICV_LEN;
+ *caplenp -= MACSEC_DEFAULT_ICV_LEN;
+ /*
+ * Update the snapend thus the ICV field is not in the payload for
+ * the caller.
+ * The ICV (Integrity Check Value) is at the end of the frame, after
+ * the secure data.
+ */
+ ndo->ndo_snapend -= MACSEC_DEFAULT_ICV_LEN;
+
+ /*
+ * If the SL field is non-zero, then it's the length of the
+ * Secure Data; otherwise, the Secure Data is what's left
+ * ver after the MACsec header and ICV are removed.
+ */
+ if (short_length != 0) {
+ /*
+ * If the short length is more than we *have*,
+ * that's an error.
+ */
+ if (short_length > *lengthp) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
+ return hdrlen + caplen;
+ }
+ if (short_length > *caplenp) {
+ nd_print_trunc(ndo);
+ ndo->ndo_protocol = save_protocol;
+ return hdrlen + caplen;
+ }
+ if (*lengthp > short_length)
+ *lengthp = short_length;
+ if (*caplenp > short_length)
+ *caplenp = short_length;
+ }
+
+ ndo->ndo_protocol = save_protocol;
+ return -1;
}
projects / tcpdump / blobdiff