RF455-097 RF 4.55: class attack skills (Bash Explosion, Force Impact, Fatal Step…) deal the wrong damage: the server looks their index up in the general `skill` table

Game: RF 4.55 (Dragonborn), server v0.3.1, Windows build (stock gameserver.exe). Client: the supported Taiwan build, RF_Online.bin SHA-256 46528aac…2bbc558 (2025-07-16), Language=Taiwan. Data: the shipped db\gamedata_rf455.db.

Summary

The client sends a damaging class skill as 05/02 attack_skill_request, the same message as a general attack skill, with the class-skill row index. GoMMO looks that index up in the skill table (84 general skills), never in classskill. So no class attack skill gets its own damage:

• an index past 83 has no skill row, and gets a default multiplier (about +63% at level 1 GM);
• an index under 84 picks up an unrelated general skill's row. Bellato's and Cora's Bash Explosion (rows 16, 57), Judgment (9) and Full Swing (48) land on rows with formula −1 and attack constant 0, which gives a zero damage band. Double Crash (6) gets Death Blow's 155%.

Their own data (and rfdatabase.net) says 218–596%. Read from the code and data (static); not live-tested.

The client (read, RF_Online.bin)

• The skill-use dispatch 0x413a80 tests the category byte ([action+0x5c], 2 = class skill; 0x4070f0) and "attackable" (0x4638f0 → 0x463960). A skill is attackable when, on any level, the per-level byte at SkillForce.edf record +0x90 + 0x28·L is 0 or 4.
• Attackable → 05/02, sender 0x5a4ac0. Not attackable → 11/07, sender 0x5a0790.
• The 05/02 body has the category byte (2) at offset 3 and the u16 skill index at offset 4, taken from action[+4] (0x40b200). The 11/07 sender takes its index from the same field, and live 11/07 requests in history.log carry classskill row indices (217, 228). So 05/02 carries the classskill row index too (inferred from the shared field; no class-skill 05/02 was captured).
• 22 class skills pass the test: every row in the table below.

The server (read, v0.3.1)

• handleAttackSkill 0x1407d9d60 passes the index to SkillAttackFor 0x140525660 → loadSkillAttack 0x1405258a0, a query on the skill table by m_dwIndex.
• The category byte goes only to resolveSFEffectOK. There is no branch for class skills, and no loader that reads classskill's m_nAttConstant / m_fAttFormulaConstant (loadClassSkillGroupsFrom 0x1407c21e0 and buildSFEffectColumns 0x140527f40 take neither).
• skillAttackPoint 0x1408d5ac0:
  • with a row: formula × attConst[L] / 788 × (0.847 + 0.86472·(0.5L+3.5)/7 + 0.28824·M/99) (row +0x40, +8);
  • with no row (test r8, r8 / je 0x1408d5b30): formula 1.0 (0x140d7ca94) and attConst 788.0 (0x140d7cb2c).
• handleClassSkillCast (11/07) computes no damage at all.

Every class skill the client sends as 05/02 (Credit to RFDB for http://rfdatabase.net)

"data" is the class skill's own multiplier (its formula constant, attack constant taken as 788, level 1, GM). It equals rfdatabase.net's "Skill damage output". "server" is what skillAttackPoint computes for the index it receives. −100% is a zero band (formula −1 × attConst 0); how much a zero band finally hits for wasn't traced.

code   row  name                 data (attConst as 788)  server (level 1, GM)
7001E  6    DoubleCrash            218%                    155%  skill row 6 Death Blow (formula 1.5625, attConst 788)
70021  9    Judgment               218%                   -100%  skill row 9 Aid Stretching (formula -1, attConst 0)
70008  16   BashExplosion          377%                   -100%  skill row 16 Slam (formula -1, attConst 0)
80048  48   FullSwing              298%                   -100%  skill row 48 Booster (formula -1, attConst 0)
80008  57   BashExplosion          377%                   -100%  skill row 57 Offence wave (formula -1, attConst 0)
4006C  84   Mangle                 218%                     63%  no skill row, default 1.0/788
40008  100  BashExplosion          377%                     63%  no skill row, default 1.0/788
71099  132  EagleCrusher           298%                     63%  no skill row, default 1.0/788
700A2  138  FatalStep              596%                     63%  no skill row, default 1.0/788
7100C  141  SDFiring               298%                     63%  no skill row, default 1.0/788
810C1  169  FirstStrikeShot        218%                     63%  no skill row, default 1.0/788
800CC  180  SilenceStep            596%                     63%  no skill row, default 1.0/788
8100C  183  SDFiring               298%                     63%  no skill row, default 1.0/788
410EB  211  AminingLauncher        218%                     63%  no skill row, default 1.0/788
410EC  212  CompoundSiege          298%                     63%  no skill row, default 1.0/788
410ED  216  DesperationLauncher    298%                     63%  no skill row, default 1.0/788
410EF  218  MightblastSiege        397%                     63%  no skill row, default 1.0/788
400F6  222  IllusionAttack         596%                     63%  no skill row, default 1.0/788
4100C  225  SDFiring               298%                     63%  no skill row, default 1.0/788
7011B  259  DeadlyStaff            218%                     63%  no skill row, default 1.0/788
7111C  260  ForceImpact            397%                     63%  no skill row, default 1.0/788
81146  302  StrikingForce          397%                     63%  no skill row, default 1.0/788

Three of these rows carry attack constant 7880, not 788 (Deadly Staff, Force Impact, Striking Force). Read as-is, that would be ten times the site's value, so it may need checking too if class skills get their own loader.

How to reproduce

On one monster, compare a few normal hits with a few casts of:

• Bash Explosion as Accretia Mercenary (row 100): about a weak skill, far below 3.8×;
• Bash Explosion as Bellato Shield Miller (row 16) or Cora Black Knight (row 57): next to nothing.

Related reports

• RF455-093New: class skills sent as 11/07 lose their instant effects. This report is the other path: class skills the client sends as 05/02.
• RF455-030Released (released 0.1.2) rebuilt 12 class skills in classskill and RF455-092New follows it up (names). Neither touches class-skill damage.
• RF455-051Released (splash targets on 05/02) and RF455-046Released (the damage number's display) are about the same message, but not about where the damage values come from.

Suggested fix

In handleAttackSkill, when the category byte at offset 3 is 2 (class skill), load the attack row from classskill (the same columns loadSkillAttack reads from skill) instead of skill.