filter compiler: fix handling of some DLT_ values.

guyharris · guyharris · commit ec782d07e7ef · 2025-06-24T17:53:07.000-07:00
Add explicit cases for the remaining assigned values, supporting only
raw "link[N:M]" filtering.

For values that aren't assigned, don't put a range in the error message;
there are valid values outside that range (e.g., 1 is used for some
obscure technology DEC, Intel, and Xerox standardized, running on a
thick yellow cable, and its successors).
diff --git a/gencode.c b/gencode.c
@@ -2135,6 +2135,83 @@ init_linktype(compiler_state_t *cstate, pcap_t *p)
 		cstate->off_nl_nosnap = 3;	/* 802.3+802.2 */
 		break;
 
+	case DLT_EN3MB:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+	case DLT_AX25:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+	case DLT_PRONET:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+	case DLT_CHAOS:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+#ifdef DLT_HIPPI
+	case DLT_HIPPI:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+#endif
+
+	case DLT_REDBACK_SMARTEDGE:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+
+#ifdef DLT_HHDLC
+	case DLT_HHDLC:
+		/*
+		 * Currently, only raw "link[N:M]" filtering is supported.
+		 */
+		cstate->off_linktype.constant_part = OFFSET_NOT_SET;	/* variable, min 15, max 71 steps of 7 */
+		cstate->off_linkpl.constant_part = OFFSET_NOT_SET;
+		cstate->off_nl = OFFSET_NOT_SET;	/* variable, min 16, max 71 steps of 7 */
+		cstate->off_nl_nosnap = OFFSET_NOT_SET;	/* no 802.2 LLC */
+		break;
+
+#endif
+
 	default:
 		/*
 		 * For values in the range in which we've assigned new
@@ -2147,8 +2224,8 @@ init_linktype(compiler_state_t *cstate, pcap_t *p)
 			cstate->off_nl = OFFSET_NOT_SET;
 			cstate->off_nl_nosnap = OFFSET_NOT_SET;
 		} else {
-			bpf_set_error(cstate, "unknown data link type %d (min %d, max %d)",
-			    cstate->linktype, DLT_HIGH_MATCHING_MIN, DLT_HIGH_MATCHING_MAX);
+			bpf_set_error(cstate, "unknown data link type %d",
+			    cstate->linktype);
 			return (-1);
 		}
 		break;
