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1 | 1 | package leases |
2 | 2 |
|
3 | 3 | import ( |
4 | | - "errors" |
5 | | - "regexp" |
| 4 | + "fmt" |
| 5 | + "log/slog" |
| 6 | + "net/netip" |
| 7 | + "strings" |
6 | 8 | "time" |
7 | 9 | ) |
8 | 10 |
|
9 | 11 | const ( |
10 | 12 | leaseDateFormat = "2006/01/02 15:04:05" |
11 | | - leaseRegex = `(?ms)lease\s+(?P<ip>[^\s]+)\s+{.*?starts\s\d+\s(?P<begin>[\d\/]+\s[\d\:]+);.*?ends\s\d+\s(?P<end>[\d\/]+\s[\d\:]+);.*?hardware\sethernet\s(?P<mac>[\w\:]+);.*?}` |
12 | 13 | ) |
13 | 14 |
|
14 | | -func parse(contents string) (Leases, error) { |
15 | | - leases := Leases{} |
16 | | - var re = regexp.MustCompile(leaseRegex) |
17 | | - matches := re.FindAllStringSubmatch(contents, -1) |
18 | | - var errs []error |
19 | | - for _, m := range matches { |
20 | | - rm := make(map[string]string) |
21 | | - for i, name := range re.SubexpNames() { |
22 | | - if i != 0 && name != "" { |
23 | | - rm[name] = m[i] |
24 | | - } |
25 | | - } |
26 | | - begin, err := time.Parse(leaseDateFormat, rm["begin"]) |
27 | | - if err != nil { |
28 | | - errs = append(errs, err) |
29 | | - } |
30 | | - end, err := time.Parse(leaseDateFormat, rm["end"]) |
31 | | - if err != nil { |
32 | | - errs = append(errs, err) |
| 15 | +func parseLeasesFile(log *slog.Logger, data string) (Leases, error) { |
| 16 | + var ( |
| 17 | + leases Leases |
| 18 | + current *Lease |
| 19 | + ) |
| 20 | + |
| 21 | + for i, line := range strings.Split(data, "\n") { |
| 22 | + line = strings.TrimSpace(line) |
| 23 | + |
| 24 | + tokens := strings.Fields(line) |
| 25 | + if len(tokens) == 0 { |
| 26 | + continue |
33 | 27 | } |
34 | 28 |
|
35 | | - l := Lease{ |
36 | | - Mac: rm["mac"], |
37 | | - Ip: rm["ip"], |
38 | | - Begin: begin, |
39 | | - End: end, |
| 29 | + switch tokens[0] { |
| 30 | + case "lease": |
| 31 | + // lease 1.2.3.4 { |
| 32 | + if len(tokens) != 3 { |
| 33 | + return nil, fmt.Errorf(`expecting "lease <ip> {" on line %d, got: %s`, i+1, line) |
| 34 | + } |
| 35 | + |
| 36 | + if tokens[2] != "{" { |
| 37 | + return nil, fmt.Errorf("missing opening brace on line %d: %s", i+1, line) |
| 38 | + } |
| 39 | + |
| 40 | + if _, err := netip.ParseAddr(tokens[1]); err != nil { |
| 41 | + return nil, fmt.Errorf("invalid ip address on line %d: %w", i+1, err) |
| 42 | + } |
| 43 | + |
| 44 | + current = &Lease{ |
| 45 | + Ip: tokens[1], |
| 46 | + } |
| 47 | + |
| 48 | + case "}": |
| 49 | + if current == nil { |
| 50 | + return nil, fmt.Errorf("unexpected closing brace on line %d: %s", i+1, line) |
| 51 | + } |
| 52 | + |
| 53 | + switch { |
| 54 | + case current.Begin.IsZero(), current.End.IsZero(): |
| 55 | + log.Warn("incomplete lease entry (missing begin and end time), skipping entry", "line", i+1) |
| 56 | + continue |
| 57 | + case current.Ip == "": |
| 58 | + log.Warn("incomplete lease entry (missing ip address), skipping entry", "line", i+1) |
| 59 | + continue |
| 60 | + case current.Mac == "": |
| 61 | + log.Warn("incomplete lease entry (missing mac address), skipping entry", "line", i+1) |
| 62 | + continue |
| 63 | + default: |
| 64 | + leases = append(leases, *current) |
| 65 | + current = nil |
| 66 | + } |
| 67 | + |
| 68 | + case "starts", "ends": |
| 69 | + // starts 5 2026/01/09 12:35:39; |
| 70 | + if current == nil { |
| 71 | + return nil, fmt.Errorf("unexpected date field on line %d: %s", i+1, line) |
| 72 | + } |
| 73 | + |
| 74 | + if len(tokens) != 4 { |
| 75 | + return nil, fmt.Errorf(`expecting "%s <whatever-number> <date> <time>;" on line %d, got: %s`, tokens[0], i+1, line) |
| 76 | + } |
| 77 | + |
| 78 | + if !strings.HasSuffix(tokens[3], ";") { |
| 79 | + return nil, fmt.Errorf("missing semicolon on line %d: %s", i+1, line) |
| 80 | + } |
| 81 | + |
| 82 | + tokens[3] = strings.TrimRight(tokens[3], ";") |
| 83 | + |
| 84 | + t, err := time.Parse(leaseDateFormat, tokens[2]+" "+tokens[3]) |
| 85 | + if err != nil { |
| 86 | + return nil, fmt.Errorf("invalid time format on line %d: %w", i+1, err) |
| 87 | + } |
| 88 | + |
| 89 | + if tokens[0] == "starts" { |
| 90 | + current.Begin = t |
| 91 | + } else { |
| 92 | + current.End = t |
| 93 | + } |
| 94 | + |
| 95 | + case "hardware": |
| 96 | + // hardware ethernet 50:7c:6f:3e:8d:59; |
| 97 | + if current == nil { |
| 98 | + return nil, fmt.Errorf("unexpected hardware field on line %d: %s", i+1, line) |
| 99 | + } |
| 100 | + |
| 101 | + if len(tokens) != 3 { |
| 102 | + return nil, fmt.Errorf(`expecting "hardware ethernet <mac>;" on line %d, got: %s`, i+1, line) |
| 103 | + } |
| 104 | + |
| 105 | + if tokens[1] != "ethernet" { |
| 106 | + continue |
| 107 | + } |
| 108 | + |
| 109 | + if !strings.HasSuffix(tokens[2], ";") { |
| 110 | + return nil, fmt.Errorf("missing semicolon on line %d: %s", i+1, line) |
| 111 | + } |
| 112 | + |
| 113 | + current.Mac = strings.TrimRight(tokens[2], ";") |
40 | 114 | } |
41 | | - leases = append(leases, l) |
42 | 115 | } |
43 | | - if len(errs) > 0 { |
44 | | - return leases, errors.Join(errs...) |
| 116 | + |
| 117 | + if current != nil { |
| 118 | + return nil, fmt.Errorf("lease entry was not closed") |
45 | 119 | } |
| 120 | + |
46 | 121 | return leases, nil |
47 | 122 | } |
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