| 1 | // SPDX-License-Identifier: GPL-3.0-or-later |
| 2 | |
| 3 | package parity |
| 4 | |
| 5 | import ( |
| 6 | "bufio" |
| 7 | "fmt" |
| 8 | "io" |
| 9 | "os" |
| 10 | "regexp" |
| 11 | "sort" |
| 12 | "strconv" |
| 13 | "strings" |
| 14 | ) |
| 15 | |
| 16 | var snmpWalkLineRE = regexp.MustCompile(`^\s*\.?([0-9][0-9.]*)\s*=\s*([^:]+):\s*(.*)$`) |
| 17 | |
| 18 | // WalkRecord is one normalized SNMP walk row. |
| 19 | type WalkRecord struct { |
| 20 | OID string `json:"oid" yaml:"oid"` |
| 21 | Type string `json:"type" yaml:"type"` |
| 22 | Value string `json:"value" yaml:"value"` |
| 23 | } |
| 24 | |
| 25 | // WalkDataset is a parsed SNMP walk fixture with deterministic ordering. |
| 26 | type WalkDataset struct { |
| 27 | Path string `json:"path" yaml:"path"` |
| 28 | Records []WalkRecord `json:"records" yaml:"records"` |
| 29 | byOID map[string]WalkRecord |
| 30 | } |
| 31 | |
| 32 | // LoadWalkFile parses a walk file in OpenNMS snmpwalk format. |
| 33 | func LoadWalkFile(path string) (WalkDataset, error) { |
| 34 | f, err := os.Open(path) |
| 35 | if err != nil { |
| 36 | return WalkDataset{}, fmt.Errorf("open walk file %q: %w", path, err) |
| 37 | } |
| 38 | |
| 39 | records, err := ParseWalk(f) |
| 40 | if closeErr := f.Close(); err == nil && closeErr != nil { |
| 41 | return WalkDataset{}, fmt.Errorf("close walk file %q: %w", path, closeErr) |
| 42 | } |
| 43 | if err != nil { |
| 44 | return WalkDataset{}, fmt.Errorf("parse walk file %q: %w", path, err) |
| 45 | } |
| 46 | |
| 47 | ds := WalkDataset{Path: path, Records: records, byOID: make(map[string]WalkRecord, len(records))} |
| 48 | for _, rec := range records { |
| 49 | ds.byOID[rec.OID] = rec |
| 50 | } |
| 51 | return ds, nil |
| 52 | } |
| 53 | |
| 54 | // ParseWalk parses OpenNMS snmpwalk text records. |
| 55 | func ParseWalk(r io.Reader) ([]WalkRecord, error) { |
| 56 | scanner := bufio.NewScanner(r) |
| 57 | scanner.Buffer(make([]byte, 0, 64*1024), 16*1024*1024) |
| 58 | |
| 59 | type partial struct { |
| 60 | oid string |
| 61 | typ string |
| 62 | value strings.Builder |
| 63 | quoteOpen bool |
| 64 | escaped bool |
| 65 | } |
| 66 | |
| 67 | var ( |
| 68 | lineNo int |
| 69 | records []WalkRecord |
| 70 | cur *partial |
| 71 | ) |
| 72 | |
| 73 | flush := func() { |
| 74 | if cur == nil { |
| 75 | return |
| 76 | } |
| 77 | records = append(records, WalkRecord{ |
| 78 | OID: cur.oid, |
| 79 | Type: cur.typ, |
| 80 | Value: normalizeWalkValue(cur.value.String()), |
| 81 | }) |
| 82 | cur = nil |
| 83 | } |
| 84 | |
| 85 | for scanner.Scan() { |
| 86 | lineNo++ |
| 87 | line := strings.TrimRight(scanner.Text(), "\r") |
| 88 | if strings.TrimSpace(line) == "" { |
| 89 | if cur != nil { |
| 90 | cur.value.WriteByte('\n') |
| 91 | cur.quoteOpen, cur.escaped = updateQuoteState("\n", cur.quoteOpen, cur.escaped) |
| 92 | } |
| 93 | continue |
| 94 | } |
| 95 | |
| 96 | if cur != nil { |
| 97 | if cur.value.Len() > 0 { |
| 98 | cur.value.WriteByte('\n') |
| 99 | cur.quoteOpen, cur.escaped = updateQuoteState("\n", cur.quoteOpen, cur.escaped) |
| 100 | } |
| 101 | cur.value.WriteString(line) |
| 102 | cur.quoteOpen, cur.escaped = updateQuoteState(line, cur.quoteOpen, cur.escaped) |
| 103 | if !cur.quoteOpen { |
| 104 | cur.quoteOpen = false |
| 105 | flush() |
| 106 | } |
| 107 | continue |
| 108 | } |
| 109 | |
| 110 | match := snmpWalkLineRE.FindStringSubmatch(line) |
| 111 | if len(match) != 4 { |
| 112 | // Ignore non-record lines; these appear in a few vendor dumps. |
| 113 | continue |
| 114 | } |
| 115 | |
| 116 | oid := normalizeOID(match[1]) |
| 117 | typ := strings.TrimSpace(match[2]) |
| 118 | value := match[3] |
| 119 | if oid == "" || typ == "" { |
| 120 | continue |
| 121 | } |
| 122 | |
| 123 | quoteOpen, escaped := updateQuoteState(value, false, false) |
| 124 | if quoteOpen { |
| 125 | cur = &partial{oid: oid, typ: typ, quoteOpen: quoteOpen, escaped: escaped} |
| 126 | cur.value.WriteString(value) |
| 127 | continue |
| 128 | } |
| 129 | |
| 130 | records = append(records, WalkRecord{ |
| 131 | OID: oid, |
| 132 | Type: typ, |
| 133 | Value: normalizeWalkValue(value), |
| 134 | }) |
| 135 | } |
| 136 | |
| 137 | if err := scanner.Err(); err != nil { |
| 138 | return nil, fmt.Errorf("scan walk line %d: %w", lineNo, err) |
| 139 | } |
| 140 | if cur != nil && cur.quoteOpen { |
| 141 | return nil, fmt.Errorf("unterminated quoted value for OID %s", cur.oid) |
| 142 | } |
| 143 | return records, nil |
| 144 | } |
| 145 | |
| 146 | // Lookup returns one record by OID. OID matching ignores leading dots. |
| 147 | func (d *WalkDataset) Lookup(oid string) (WalkRecord, bool) { |
| 148 | if d == nil { |
| 149 | return WalkRecord{}, false |
| 150 | } |
| 151 | if len(d.byOID) == 0 { |
| 152 | index := make(map[string]WalkRecord, len(d.Records)) |
| 153 | for _, rec := range d.Records { |
| 154 | index[rec.OID] = rec |
| 155 | } |
| 156 | d.byOID = index |
| 157 | } |
| 158 | rec, ok := d.byOID[normalizeOID(oid)] |
| 159 | return rec, ok |
| 160 | } |
| 161 | |
| 162 | // Prefix returns all records with the given OID prefix, in file order. |
| 163 | func (d WalkDataset) Prefix(prefix string) []WalkRecord { |
| 164 | norm := normalizeOID(prefix) |
| 165 | if norm == "" { |
| 166 | out := make([]WalkRecord, len(d.Records)) |
| 167 | copy(out, d.Records) |
| 168 | return out |
| 169 | } |
| 170 | out := make([]WalkRecord, 0) |
| 171 | for _, rec := range d.Records { |
| 172 | if strings.HasPrefix(rec.OID, norm) { |
| 173 | out = append(out, rec) |
| 174 | } |
| 175 | } |
| 176 | return out |
| 177 | } |
| 178 | |
| 179 | // SortedOIDs returns deterministic OID ordering from the dataset. |
| 180 | func (d WalkDataset) SortedOIDs() []string { |
| 181 | oids := make([]string, 0, len(d.Records)) |
| 182 | for _, rec := range d.Records { |
| 183 | oids = append(oids, rec.OID) |
| 184 | } |
| 185 | sort.Slice(oids, func(i, j int) bool { |
| 186 | return compareOID(oids[i], oids[j]) < 0 |
| 187 | }) |
| 188 | return oids |
| 189 | } |
| 190 | |
| 191 | func compareOID(a, b string) int { |
| 192 | partsA := strings.Split(a, ".") |
| 193 | partsB := strings.Split(b, ".") |
| 194 | limit := min(len(partsB), len(partsA)) |
| 195 | |
| 196 | for i := range limit { |
| 197 | if partsA[i] == partsB[i] { |
| 198 | continue |
| 199 | } |
| 200 | |
| 201 | numA, errA := strconv.Atoi(partsA[i]) |
| 202 | numB, errB := strconv.Atoi(partsB[i]) |
| 203 | if errA == nil && errB == nil { |
| 204 | switch { |
| 205 | case numA < numB: |
| 206 | return -1 |
| 207 | case numA > numB: |
| 208 | return 1 |
| 209 | default: |
| 210 | continue |
| 211 | } |
| 212 | } |
| 213 | |
| 214 | if partsA[i] < partsB[i] { |
| 215 | return -1 |
| 216 | } |
| 217 | return 1 |
| 218 | } |
| 219 | |
| 220 | switch { |
| 221 | case len(partsA) < len(partsB): |
| 222 | return -1 |
| 223 | case len(partsA) > len(partsB): |
| 224 | return 1 |
| 225 | default: |
| 226 | return 0 |
| 227 | } |
| 228 | } |
| 229 | |
| 230 | func normalizeOID(v string) string { |
| 231 | return strings.TrimLeft(strings.TrimSpace(v), ".") |
| 232 | } |
| 233 | |
| 234 | func normalizeWalkValue(v string) string { |
| 235 | s := strings.TrimSpace(v) |
| 236 | if len(s) >= 2 && strings.HasPrefix(s, `"`) && strings.HasSuffix(s, `"`) { |
| 237 | s = strings.TrimPrefix(s, `"`) |
| 238 | s = strings.TrimSuffix(s, `"`) |
| 239 | } |
| 240 | s = strings.ReplaceAll(s, `\"`, `"`) |
| 241 | return s |
| 242 | } |
| 243 | |
| 244 | func updateQuoteState(v string, quoteOpen, escaped bool) (bool, bool) { |
| 245 | for i := 0; i < len(v); i++ { |
| 246 | ch := v[i] |
| 247 | if escaped { |
| 248 | escaped = false |
| 249 | continue |
| 250 | } |
| 251 | if ch == '\\' { |
| 252 | escaped = true |
| 253 | continue |
| 254 | } |
| 255 | if ch == '"' { |
| 256 | quoteOpen = !quoteOpen |
| 257 | } |
| 258 | } |
| 259 | return quoteOpen, escaped |
| 260 | } |